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authorDimitri John Ledkov <xnox@ubuntu.com>2018-07-23 14:32:01 +0100
committerDimitri John Ledkov <xnox@ubuntu.com>2018-07-23 14:32:01 +0100
commit3b9cf4c8cda0818e4d3f9892ece9f7d99de13b03 (patch)
tree59446f505b5bb3b31b1b3bb81af997dda68407c2 /m4/btrfs_detect_cstd.m4
parentf22f0302575d3a167ee550470c922de82e34342b (diff)
Diffstat (limited to 'm4/btrfs_detect_cstd.m4')
-rw-r--r--m4/btrfs_detect_cstd.m420
1 files changed, 20 insertions, 0 deletions
diff --git a/m4/btrfs_detect_cstd.m4 b/m4/btrfs_detect_cstd.m4
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+++ b/m4/btrfs_detect_cstd.m4
@@ -0,0 +1,20 @@
+dnl We prefer -std=gnu90 but gcc versions prior to 4.5.0 don't support
+dnl it. AX_CHECK_COMPILE_FLAG is the right way to determine whether a
+dnl particular version of gcc supports a flag, but it requires autoconf
+dnl 2.64. Since (for now) we still want to support older releases
+dnl that ship with autoconf 2.63, we the also-deprecated AX_GCC_VERSION
+dnl macro there.
+AC_DEFUN([BTRFS_DETECT_CSTD],
+[
+ m4_version_prereq([2.64], [
+ AX_CHECK_COMPILE_FLAG([-std=gnu90],
+ [BTRFS_CSTD_FLAGS=-std=gnu90],
+ [BTRFS_CSTD_FLAGS=-std=gnu89])
+ ], [
+ AX_GCC_VERSION([4], [5], [0],
+ [BTRFS_CSTD_FLAGS=-std=gnu90],
+ [BTRFS_CSTD_FLAGS=-std=gnu89])
+ ])
+ AC_SUBST([BTRFS_CSTD_FLAGS])
+]) dnl BTRFS_DETECT_CSTD
+