Build: Fix bugs in the CMake files.

Seems that the phrase "add more quotes" from sh/bash scripting
applies to CMake as well. E.g. passing an unquoted list ${FOO}
to a function that expects one argument results in only the
first element of the list being passed as an argument and
the rest get ignored. Adding quotes helps ("${FOO}").

list(INSERT ...) is weird. Inserting an empty string to an empty
variable results in empty list, but inserting it to a non-empty
variable does insert an empty element to the list.

Since INSERT requires at least one element,
"${CMAKE_THREAD_LIBS_INIT}" needs to be quoted in CMakeLists.txt.
It might result in an empty element in the list. It seems to not
matter as empty elements consistently get ignored in that variable.
In fact, calling cmake_check_push_state() and cmake_check_pop_state()
will strip the empty elements from CMAKE_REQUIRED_LIBRARIES!

In addition to quoting fixes, this fixes checks for the cache
variables in tuklib_cpucores.cmake and tuklib_physmem.cmake.

Thanks to Martin Matuška for testing and reporting the problems.
These fixes aren't tested yet but hopefully they soon will be.

7 files changed, 85 insertions, 78 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5b840b46..7767896e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -65,10 +65,10 @@ string(REGEX REPLACE
 #define LZMA_VERSION_MINOR ([0-9]+)\n\
 #define LZMA_VERSION_PATCH ([0-9]+)\n\
 .*$"
-       "\\1.\\2.\\3" XZ_VERSION ${XZ_VERSION})
+       "\\1.\\2.\\3" XZ_VERSION "${XZ_VERSION}")
 
 # Among other things, this gives us variables xz_VERSION and xz_VERSION_MAJOR.
-project(xz VERSION ${XZ_VERSION} LANGUAGES C)
+project(xz VERSION "${XZ_VERSION}" LANGUAGES C)
 
 # Definitions common to all targets:
 add_compile_definitions(
@@ -152,7 +152,7 @@ if(NOT WIN32 AND NOT DEFINED CACHE{HAVE_CLOCK_GETTIME})
         # when clock_gettime is available.
         add_compile_definitions(
             HAVE_CLOCK_GETTIME
-            HAVE_DECL_CLOCK_MONOTONIC=$<BOOL:${HAVE_DECL_CLOCK_MONOTONIC}>
+            HAVE_DECL_CLOCK_MONOTONIC=$<BOOL:"${HAVE_DECL_CLOCK_MONOTONIC}">
         )
     endif()
 endif()
@@ -167,7 +167,7 @@ else()
 
     # Check if pthread_condattr_setclock() exists to use CLOCK_MONOTONIC.
     if(HAVE_DECL_CLOCK_MONOTONIC)
-        list(INSERT CMAKE_REQUIRED_LIBRARIES 0 ${CMAKE_THREAD_LIBS_INIT})
+        list(INSERT CMAKE_REQUIRED_LIBRARIES 0 "${CMAKE_THREAD_LIBS_INIT}")
         check_symbol_exists(pthread_condattr_setclock pthread.h
                             HAVE_PTHREAD_CONDATTR_SETCLOCK)
         tuklib_add_definition_if(ALL HAVE_PTHREAD_CONDATTR_SETCLOCK)
@@ -395,11 +395,11 @@ if(WIN32)
 elseif(CMAKE_SYSTEM_NAME MATCHES "^Linux$|^FreeBSD$")
     # Symbol versioning for shared liblzma. This doesn't affect static builds.
     target_link_options(liblzma PRIVATE
-        -Wl,--version-script=${CMAKE_CURRENT_SOURCE_DIR}/src/liblzma/liblzma.map
+        "-Wl,--version-script=${CMAKE_CURRENT_SOURCE_DIR}/src/liblzma/liblzma.map"
     )
     set_target_properties(liblzma PROPERTIES
-        LINK_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/src/liblzma/liblzma.map
-        LINK_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/src/common/common_w32res.rc
+        LINK_DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/src/liblzma/liblzma.map"
+        LINK_DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/src/common/common_w32res.rc"
     )
 endif()
 
@@ -407,8 +407,8 @@ set_target_properties(liblzma PROPERTIES
     # At least for now the package versioning matches the rules used for
     # shared library versioning (excluding development releases) so it is
     # fine to use the package version here.
-    SOVERSION ${xz_VERSION_MAJOR}
-    VERSION ${xz_VERSION}
+    SOVERSION "${xz_VERSION_MAJOR}"
+    VERSION "${xz_VERSION}"
 
     # It's liblzma.so or liblzma.dll, not libliblzma.so or lzma.dll.
     # Avoid the name lzma.dll because it would conflict with LZMA SDK.
@@ -421,12 +421,12 @@ set_target_properties(liblzma PROPERTIES
 # for development releases where each release may have incompatible changes.
 include(CMakePackageConfigHelpers)
 write_basic_package_version_file(
-    ${CMAKE_CURRENT_BINARY_DIR}/liblzmaConfigVersion.cmake
-    VERSION ${liblzma_VERSION}
+    "${CMAKE_CURRENT_BINARY_DIR}/liblzmaConfigVersion.cmake"
+    VERSION "${liblzma_VERSION}"
     COMPATIBILITY SameMajorVersion)
 
 # Create liblzmaConfig.cmake.
-file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/liblzmaConfig.cmake
+file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/liblzmaConfig.cmake"
 "include(CMakeFindDependencyMacro)
 set(THREADS_PREFER_PTHREAD_FLAG TRUE)
 find_dependency(Threads)
@@ -439,36 +439,36 @@ include(GNUInstallDirs)
 # Install the library binary. The INCLUDES specifies the include path that
 # is exported for other projects to use but it doesn't install any files.
 install(TARGETS liblzma EXPORT liblzmaTargets
-        RUNTIME  DESTINATION ${CMAKE_INSTALL_BINDIR}
+        RUNTIME  DESTINATION "${CMAKE_INSTALL_BINDIR}"
                  COMPONENT liblzma_Runtime
-        LIBRARY  DESTINATION ${CMAKE_INSTALL_LIBDIR}
+        LIBRARY  DESTINATION "${CMAKE_INSTALL_LIBDIR}"
                  COMPONENT liblzma_Runtime
                  NAMELINK_COMPONENT liblzma_Development
-        ARCHIVE  DESTINATION ${CMAKE_INSTALL_LIBDIR}
+        ARCHIVE  DESTINATION "${CMAKE_INSTALL_LIBDIR}"
                  COMPONENT liblzma_Development
-        INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+        INCLUDES DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
 
 # Install the liblzma API headers. These use a subdirectory so
 # this has to be done as a separate step.
 install(DIRECTORY src/liblzma/api/
         COMPONENT liblzma_Development
-        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
         FILES_MATCHING PATTERN "*.h")
 
 # Install the CMake files that other packages can use to find liblzma.
 set(liblzma_INSTALL_CMAKEDIR
-    ${CMAKE_INSTALL_LIBDIR}/cmake/liblzma
+    "${CMAKE_INSTALL_LIBDIR}/cmake/liblzma"
     CACHE STRING "Path to liblzma's .cmake files")
 
 install(EXPORT liblzmaTargets
         NAMESPACE liblzma::
         FILE liblzmaTargets.cmake
-        DESTINATION ${liblzma_INSTALL_CMAKEDIR}
+        DESTINATION "${liblzma_INSTALL_CMAKEDIR}"
         COMPONENT liblzma_Development)
 
-install(FILES ${CMAKE_CURRENT_BINARY_DIR}/liblzmaConfig.cmake
-              ${CMAKE_CURRENT_BINARY_DIR}/liblzmaConfigVersion.cmake
-        DESTINATION ${liblzma_INSTALL_CMAKEDIR}
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/liblzmaConfig.cmake"
+              "${CMAKE_CURRENT_BINARY_DIR}/liblzmaConfigVersion.cmake"
+        DESTINATION "${liblzma_INSTALL_CMAKEDIR}"
         COMPONENT liblzma_Development)
 
 
@@ -507,12 +507,12 @@ if(HAVE_GETOPT_LONG)
     tuklib_progname(xzdec)
 
     install(TARGETS xzdec
-            RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+            RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
                     COMPONENT xzdec)
 
     if(UNIX)
         install(FILES src/xzdec/xzdec.1
-                DESTINATION ${CMAKE_INSTALL_MANDIR}/man1
+                DESTINATION "${CMAKE_INSTALL_MANDIR}/man1"
                 COMPONENT xzdec)
     endif()
 endif()
@@ -634,10 +634,10 @@ if(NOT MSVC AND HAVE_GETOPT_LONG)
     endif()
 
     install(TARGETS xz
-            RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+            RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
                     COMPONENT xz)
 
     install(FILES src/xz/xz.1
-            DESTINATION ${CMAKE_INSTALL_MANDIR}/man1
+            DESTINATION "${CMAKE_INSTALL_MANDIR}/man1"
             COMPONENT xz)
 endif()
diff --git a/cmake/tuklib_common.cmake b/cmake/tuklib_common.cmake
index c3d2c536..088a3cb1 100644
--- a/cmake/tuklib_common.cmake
+++ b/cmake/tuklib_common.cmake
@@ -8,16 +8,18 @@
 #
 
 function(tuklib_add_definitions TARGET_OR_ALL DEFINITIONS)
+    # DEFINITIONS may be an empty string/list but it's fine here. There is
+    # no need to quote ${DEFINITIONS} as empty arguments are fine here.
     if(TARGET_OR_ALL STREQUAL "ALL")
         add_compile_definitions(${DEFINITIONS})
     else()
-        target_compile_definitions(${TARGET_OR_ALL} PRIVATE ${DEFINITIONS})
+        target_compile_definitions("${TARGET_OR_ALL}" PRIVATE ${DEFINITIONS})
     endif()
 endfunction()
 
 function(tuklib_add_definition_if TARGET_OR_ALL VAR)
     if(${VAR})
-        tuklib_add_definitions(${TARGET_OR_ALL} ${VAR})
+        tuklib_add_definitions("${TARGET_OR_ALL}" "${VAR}")
     endif()
 endfunction()
 
@@ -28,7 +30,7 @@ macro(tuklib_use_system_extensions TARGET_OR_ALL)
         # FIXME? The Solaris-specific __EXTENSIONS__ should be conditional
         #        even on Solaris. See gnulib: git log m4/extensions.m4.
         # FIXME? gnulib and autoconf.git has lots of new stuff.
-        tuklib_add_definitions(${TARGET_OR_ALL}
+        tuklib_add_definitions("${TARGET_OR_ALL}"
             _GNU_SOURCE
             __EXTENSIONS__
             _POSIX_PTHREAD_SEMANTICS
diff --git a/cmake/tuklib_cpucores.cmake b/cmake/tuklib_cpucores.cmake
index 34546b0d..5844e4b2 100644
--- a/cmake/tuklib_cpucores.cmake
+++ b/cmake/tuklib_cpucores.cmake
@@ -7,15 +7,11 @@
 # You can do whatever you want with this file.
 #
 
-include(${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake)
+include("${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake")
 include(CheckCSourceCompiles)
 include(CheckIncludeFile)
 
 function(tuklib_cpucores_internal_check)
-    if(CACHE{TUKLIB_CPUCORES_DEFINITIONS})
-        return()
-    endif()
-
     if(WIN32 OR CYGWIN)
         # Nothing to do, the tuklib_cpucores.c handles it.
         set(TUKLIB_CPUCORES_DEFINITIONS "" CACHE INTERNAL "")
@@ -158,16 +154,22 @@ function(tuklib_cpucores_internal_check)
 endfunction()
 
 function(tuklib_cpucores TARGET_OR_ALL)
-    message(STATUS "Checking how to detect the number of available CPU cores")
+    if(NOT DEFINED CACHE{TUKLIB_CPUCORES_FOUND})
+        message(STATUS
+                "Checking how to detect the number of available CPU cores")
+        tuklib_cpucores_internal_check()
 
-    tuklib_cpucores_internal_check()
+        if(DEFINED CACHE{TUKLIB_CPUCORES_DEFINITIONS})
+            set(TUKLIB_CPUCORES_FOUND 1 CACHE INTERNAL "")
+        else()
+            set(TUKLIB_CPUCORES_FOUND 0 CACHE INTERNAL "")
+            message(WARNING
+                    "No method to detect the number of CPU cores was found")
+        endif()
+    endif()
 
-    if(NOT DEFINED CACHE{TUKLIB_CPUCORES_DEFINITIONS})
-        set(TUKLIB_CPUCORES_FOUND 0 PARENT_SCOPE)
-        message(WARNING
-                "No method to detect the number of CPU cores was found")
-    else()
-        set(TUKLIB_CPUCORES_FOUND 1 PARENT_SCOPE)
-        tuklib_add_definitions(${TARGET_OR_ALL} ${TUKLIB_CPUCORES_DEFINITIONS})
+    if(TUKLIB_CPUCORES_FOUND)
+        tuklib_add_definitions("${TARGET_OR_ALL}"
+                               "${TUKLIB_CPUCORES_DEFINITIONS}")
     endif()
 endfunction()
diff --git a/cmake/tuklib_integer.cmake b/cmake/tuklib_integer.cmake
index aeb7ff6f..d7e2e28c 100644
--- a/cmake/tuklib_integer.cmake
+++ b/cmake/tuklib_integer.cmake
@@ -7,7 +7,7 @@
 # You can do whatever you want with this file.
 #
 
-include(${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake)
+include("${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake")
 include(TestBigEndian)
 include(CheckCSourceCompiles)
 include(CheckIncludeFile)
@@ -22,7 +22,7 @@ function(tuklib_integer TARGET_OR_ALL)
     if(NOT DEFINED WORDS_BIGENDIAN)
         message(FATAL_ERROR "Cannot determine endianness")
     endif()
-    tuklib_add_definition_if(${TARGET_OR_ALL} WORDS_BIGENDIAN)
+    tuklib_add_definition_if("${TARGET_OR_ALL}" WORDS_BIGENDIAN)
 
     # Look for a byteswapping method.
     check_c_source_compiles("
@@ -36,24 +36,25 @@ function(tuklib_integer TARGET_OR_ALL)
         "
         HAVE___BUILTIN_BSWAPXX)
     if(HAVE___BUILTIN_BSWAPXX)
-        tuklib_add_definitions(${TARGET_OR_ALL} HAVE___BUILTIN_BSWAPXX)
+        tuklib_add_definitions("${TARGET_OR_ALL}" HAVE___BUILTIN_BSWAPXX)
     else()
         check_include_file(byteswap.h HAVE_BYTESWAP_H)
         if(HAVE_BYTESWAP_H)
-            tuklib_add_definitions(${TARGET_OR_ALL} HAVE_BYTESWAP_H)
+            tuklib_add_definitions("${TARGET_OR_ALL}" HAVE_BYTESWAP_H)
             check_symbol_exists(bswap_16 byteswap.h HAVE_BSWAP_16)
-            tuklib_add_definition_if(${TARGET_OR_ALL} HAVE_BSWAP_16)
+            tuklib_add_definition_if("${TARGET_OR_ALL}" HAVE_BSWAP_16)
             check_symbol_exists(bswap_32 byteswap.h HAVE_BSWAP_32)
-            tuklib_add_definition_if(${TARGET_OR_ALL} HAVE_BSWAP_32)
+            tuklib_add_definition_if("${TARGET_OR_ALL}" HAVE_BSWAP_32)
             check_symbol_exists(bswap_64 byteswap.h HAVE_BSWAP_64)
-            tuklib_add_definition_if(${TARGET_OR_ALL} HAVE_BSWAP_64)
+            tuklib_add_definition_if("${TARGET_OR_ALL}" HAVE_BSWAP_64)
         else()
             check_include_file(sys/endian.h HAVE_SYS_ENDIAN_H)
             if(HAVE_SYS_ENDIAN_H)
-                tuklib_add_definitions(${TARGET_OR_ALL} HAVE_SYS_ENDIAN_H)
+                tuklib_add_definitions("${TARGET_OR_ALL}" HAVE_SYS_ENDIAN_H)
             else()
                 check_include_file(sys/byteorder.h HAVE_SYS_BYTEORDER_H)
-                tuklib_add_definition_if(${TARGET_OR_ALL} HAVE_SYS_BYTEORDER_H)
+                tuklib_add_definition_if("${TARGET_OR_ALL}"
+                                         HAVE_SYS_BYTEORDER_H)
             endif()
         endif()
     endif()
@@ -72,16 +73,17 @@ function(tuklib_integer TARGET_OR_ALL)
     #       on ARM and always assumes that unaligned is fast on ARM.
     set(FAST_UNALIGNED_GUESS OFF)
     if(CMAKE_SYSTEM_PROCESSOR MATCHES
-       [Xx3456]86|^[Xx]64|^[Aa][Mm][Dd]64|^[Aa][Rr][Mm]|^aarch|^powerpc|^ppc)
+       "[Xx3456]86|^[Xx]64|^[Aa][Mm][Dd]64|^[Aa][Rr][Mm]|^aarch|^powerpc|^ppc")
         if(NOT WORDS_BIGENDIAN OR
-           NOT CMAKE_SYSTEM_PROCESSOR MATCHES ^powerpc|^ppc)
+           NOT CMAKE_SYSTEM_PROCESSOR MATCHES "^powerpc|^ppc")
            set(FAST_UNALIGNED_GUESS ON)
         endif()
     endif()
     option(TUKLIB_FAST_UNALIGNED_ACCESS
-           "Enable if the system supports *fast* unaligned memory access with 16-bit and 32-bit integers."
-           ${FAST_UNALIGNED_GUESS})
-    tuklib_add_definition_if(${TARGET_OR_ALL} TUKLIB_FAST_UNALIGNED_ACCESS)
+           "Enable if the system supports *fast* unaligned memory access \
+with 16-bit and 32-bit integers."
+           "${FAST_UNALIGNED_GUESS}")
+    tuklib_add_definition_if("${TARGET_OR_ALL}" TUKLIB_FAST_UNALIGNED_ACCESS)
 
     # Unsafe type punning:
     option(TUKLIB_USE_UNSAFE_TYPE_PUNNING
@@ -90,11 +92,11 @@ may result in broken code. However, this might improve performance \
 in some cases, especially with old compilers \
 (e.g. GCC 3 and early 4.x on x86, GCC < 6 on ARMv6 and ARMv7)."
            OFF)
-    tuklib_add_definition_if(${TARGET_OR_ALL} TUKLIB_USE_UNSAFE_TYPE_PUNNING)
+    tuklib_add_definition_if("${TARGET_OR_ALL}" TUKLIB_USE_UNSAFE_TYPE_PUNNING)
 
     # Check for GCC/Clang __builtin_assume_aligned().
     check_c_source_compiles(
         "int main(void) { __builtin_assume_aligned(\"\", 1); return 0; }"
         HAVE___BUILTIN_ASSUME_ALIGNED)
-    tuklib_add_definition_if(${TARGET_OR_ALL} HAVE___BUILTIN_ASSUME_ALIGNED)
+    tuklib_add_definition_if("${TARGET_OR_ALL}" HAVE___BUILTIN_ASSUME_ALIGNED)
 endfunction()
diff --git a/cmake/tuklib_mbstr.cmake b/cmake/tuklib_mbstr.cmake
index a39a96b4..e073be6a 100644
--- a/cmake/tuklib_mbstr.cmake
+++ b/cmake/tuklib_mbstr.cmake
@@ -7,14 +7,14 @@
 # You can do whatever you want with this file.
 #
 
-include(${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake)
+include("${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake")
 include(CheckSymbolExists)
 
 function(tuklib_mbstr TARGET_OR_ALL)
     check_symbol_exists(mbrtowc wchar.h HAVE_MBRTOWC)
-    tuklib_add_definition_if(${TARGET_OR_ALL} HAVE_MBRTOWC)
+    tuklib_add_definition_if("${TARGET_OR_ALL}" HAVE_MBRTOWC)
 
     # NOTE: wcwidth() requires _GNU_SOURCE or _XOPEN_SOURCE on GNU/Linux.
     check_symbol_exists(wcwidth wchar.h HAVE_WCWIDTH)
-    tuklib_add_definition_if(${TARGET_OR_ALL} HAVE_WCWIDTH)
+    tuklib_add_definition_if("${TARGET_OR_ALL}" HAVE_WCWIDTH)
 endfunction()
diff --git a/cmake/tuklib_physmem.cmake b/cmake/tuklib_physmem.cmake
index dc895a15..ea5bcc46 100644
--- a/cmake/tuklib_physmem.cmake
+++ b/cmake/tuklib_physmem.cmake
@@ -10,15 +10,11 @@
 # You can do whatever you want with this file.
 #
 
-include(${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake)
+include("${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake")
 include(CheckCSourceCompiles)
 include(CheckIncludeFile)
 
 function(tuklib_physmem_internal_check)
-    if(CACHE{TUKLIB_PHYSMEM_DEFINITIONS})
-        return()
-    endif()
-
     # Shortcut on Windows:
     if(WIN32 OR CYGWIN)
         # Nothing to do, the tuklib_physmem.c handles it.
@@ -134,16 +130,21 @@ function(tuklib_physmem_internal_check)
 endfunction()
 
 function(tuklib_physmem TARGET_OR_ALL)
-    message(STATUS "Checking how to detect the amount of physical memory")
-
-    tuklib_physmem_internal_check()
+    if(NOT DEFINED CACHE{TUKLIB_PHYSMEM_FOUND})
+        message(STATUS "Checking how to detect the amount of physical memory")
+        tuklib_physmem_internal_check()
 
-    if(NOT DEFINED CACHE{TUKLIB_PHYSMEM_DEFINITIONS})
-        set(TUKLIB_PHYSMEM_FOUND 0 PARENT_SCOPE)
-        message(WARNING
+        if(DEFINED CACHE{TUKLIB_PHYSMEM_DEFINITIONS})
+            set(TUKLIB_PHYSMEM_FOUND 1 CACHE INTERNAL "")
+        else()
+            set(TUKLIB_PHYSMEM_FOUND 0 CACHE INTERNAL "")
+            message(WARNING
                 "No method to detect the amount of physical memory was found")
-    else()
-        set(TUKLIB_PHYSMEM_FOUND 1 PARENT_SCOPE)
-        tuklib_add_definitions(${TARGET_OR_ALL} ${TUKLIB_PHYSMEM_DEFINITIONS})
+        endif()
+    endif()
+
+    if(TUKLIB_PHYSMEM_FOUND)
+        tuklib_add_definitions("${TARGET_OR_ALL}"
+                               "${TUKLIB_PHYSMEM_DEFINITIONS}")
     endif()
 endfunction()
diff --git a/cmake/tuklib_progname.cmake b/cmake/tuklib_progname.cmake
index 417495e6..0fa1d3d7 100644
--- a/cmake/tuklib_progname.cmake
+++ b/cmake/tuklib_progname.cmake
@@ -7,13 +7,13 @@
 # You can do whatever you want with this file.
 #
 
-include(${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake)
+include("${CMAKE_CURRENT_LIST_DIR}/tuklib_common.cmake")
 include(CheckSymbolExists)
 
 function(tuklib_progname TARGET_OR_ALL)
     # NOTE: This glibc extension requires _GNU_SOURCE.
     check_symbol_exists(program_invocation_name errno.h
                         HAVE_DECL_PROGRAM_INVOCATION_NAME)
-    tuklib_add_definition_if(${TARGET_OR_ALL}
+    tuklib_add_definition_if("${TARGET_OR_ALL}"
                              HAVE_DECL_PROGRAM_INVOCATION_NAME)
 endfunction()