doc: note why we can't use thread_local with glibc back compat

fanquake · fanquake · commit 20a30922fbf6 · 2020-04-20T16:58:54.000+08:00
diff --git a/configure.ac b/configure.ac
@@ -861,6 +861,9 @@ AC_LINK_IFELSE([AC_LANG_SOURCE([
   ]
 )
 
+dnl thread_local is currently disabled when building with glibc back compat.
+dnl Our minimum supported glibc is 2.17, however support for thread_local
+dnl did not arrive in glibc until 2.18.
 if test "x$use_thread_local" = xyes || { test "x$use_thread_local" = xauto && test "x$use_glibc_compat" = xno; }; then
   TEMP_LDFLAGS="$LDFLAGS"
   LDFLAGS="$TEMP_LDFLAGS $PTHREAD_CFLAGS"

Original file line number	Diff line number	Diff line change
`@@ -861,6 +861,9 @@ AC_LINK_IFELSE([AC_LANG_SOURCE([`
`861`	`861`	`]`
`862`	`862`	`)`
`863`	`863`
	`864`	`+dnl thread_local is currently disabled when building with glibc back compat.`
	`865`	`+dnl Our minimum supported glibc is 2.17, however support for thread_local`
	`866`	`+dnl did not arrive in glibc until 2.18.`
`864`	`867`	`if test "x$use_thread_local" = xyes \|\| { test "x$use_thread_local" = xauto && test "x$use_glibc_compat" = xno; }; then`
`865`	`868`	`TEMP_LDFLAGS="$LDFLAGS"`
`866`	`869`	`LDFLAGS="$TEMP_LDFLAGS $PTHREAD_CFLAGS"`