From b45270d88f0de1b2e8bf510f0e370a5db4067e1f Mon Sep 17 00:00:00 2001 From: Lasse Collin Date: Mon, 24 Jun 2024 23:35:59 +0300 Subject: [PATCH] Build: Use AC_LINK_IFELSE instead of -Werror AC_COMPILE_IFELSE needed -Werror because Clang <= 14 would merely warn about the unsupported attribute and implicit function declaration. Changing to AC_LINK_IFELSE handles the implicit declaration because the symbol __crc32d is unlikely to exist in libc. Note that the other part of the check is that #include must work. If the header is missing, most compilers give an error and the linking step won't be attempted. Avoiding -Werror makes the check more robust in case CFLAGS contains warning flags that break -Werror anyway (but this isn't the only check in configure.ac that has this problem). Using AC_LINK_IFELSE also makes the check more similar to how it is done in CMakeLists.txt. (cherry picked from commit 35eb57355ad1c415a838d26192d5af84abb7cf39) --- configure.ac | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) diff --git a/configure.ac b/configure.ac index 5698cdf5..a578e5b8 100644 --- a/configure.ac +++ b/configure.ac @@ -1054,15 +1054,7 @@ AC_MSG_CHECKING([if ARM64 CRC32 instruction is usable]) AS_IF([test "x$enable_arm64_crc32" = xno], [ AC_MSG_RESULT([no, --disable-arm64-crc32 was used]) ], [ - # Set -Werror here because some versions of Clang (14 and older) - # do not report the unsupported __attribute__((__target__("+crc"))) - # or __crc32d() as an error, only as a warning. This does not need - # to be done with CMake because tests will attempt to link and the - # error will be reported then. - OLD_CFLAGS="$CFLAGS" - CFLAGS="$CFLAGS -Werror" - - AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ + AC_LINK_IFELSE([AC_LANG_SOURCE([[ #include #include @@ -1082,8 +1074,6 @@ int main(void) enable_arm64_crc32=no ]) AC_MSG_RESULT([$enable_arm64_crc32]) - - CFLAGS="$OLD_CFLAGS" ]) # Check for ARM64 CRC32 instruction runtime detection.