Use -Werror to check if the compiler supports specific options

Be default, clang treats unknown warning option as warning.
We need to use -Werror to make it an error.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: 12101111 <w12101111@gmail.com>
Closes #9927

diff --git a/config/always-compiler-options.m4 b/config/always-compiler-options.m4
index e187f6ff8fc872d7950ec4001be53c95824299e3..f903655fad25c0acbc7367792f63fb7f92be89c9 100644 (file)
--- a/config/always-compiler-options.m4
+++ b/config/always-compiler-options.m4
@@ -22,7 +22,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_ASAN], [
        AS_IF([ test "$enable_asan" = "yes" ], [
                AC_MSG_CHECKING([whether $CC supports -fsanitize=address])
                saved_cflags="$CFLAGS"
-               CFLAGS="$CFLAGS -fsanitize=address"
+               CFLAGS="$CFLAGS -Werror -fsanitize=address"
                AC_LINK_IFELSE([
                        AC_LANG_SOURCE([[ int main() { return 0; } ]])
                ], [
@@ -52,7 +52,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_FRAME_LARGER_THAN], [
        AC_MSG_CHECKING([whether $CC supports -Wframe-larger-than=<size>])
 
        saved_flags="$CFLAGS"
-       CFLAGS="$CFLAGS -Wframe-larger-than=4096"
+       CFLAGS="$CFLAGS -Werror -Wframe-larger-than=4096"
 
        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])], [
                FRAME_LARGER_THAN="-Wframe-larger-than=4096"
@@ -73,7 +73,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_FORMAT_TRUNCATION], [
        AC_MSG_CHECKING([whether $CC supports -Wno-format-truncation])
 
        saved_flags="$CFLAGS"
-       CFLAGS="$CFLAGS -Wno-format-truncation"
+       CFLAGS="$CFLAGS -Werror -Wno-format-truncation"
 
        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])], [
                NO_FORMAT_TRUNCATION=-Wno-format-truncation
@@ -100,7 +100,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_BOOL_COMPARE], [
        AC_MSG_CHECKING([whether $CC supports -Wno-bool-compare])
 
        saved_flags="$CFLAGS"
-       CFLAGS="$CFLAGS -Wbool-compare"
+       CFLAGS="$CFLAGS -Werror -Wbool-compare"
 
        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])], [
                NO_BOOL_COMPARE=-Wno-bool-compare
@@ -126,7 +126,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_UNUSED_BUT_SET_VARIABLE], [
        AC_MSG_CHECKING([whether $CC supports -Wno-unused-but-set-variable])
 
        saved_flags="$CFLAGS"
-       CFLAGS="$CFLAGS -Wunused-but-set-variable"
+       CFLAGS="$CFLAGS -Werror -Wunused-but-set-variable"
 
        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])], [
                NO_UNUSED_BUT_SET_VARIABLE=-Wno-unused-but-set-variable
@@ -147,7 +147,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_CC_NO_OMIT_FRAME_POINTER], [
        AC_MSG_CHECKING([whether $CC supports -fno-omit-frame-pointer])
 
        saved_flags="$CFLAGS"
-       CFLAGS="$CFLAGS -fno-omit-frame-pointer"
+       CFLAGS="$CFLAGS -Werror -fno-omit-frame-pointer"
 
        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [])], [
                NO_OMIT_FRAME_POINTER=-fno-omit-frame-pointer