[FFmpeg-devel] [PATCH] When checking for compiler flags, check if warnings are reported.

[Diego 'Flameeyes' Pettenò]

Some compilers, namely the Sun Studio compiler, don't abort the build
when a flag is not supported, but just throw a warning. With these
changes, the output of the compiler is logged down, and can be grepped
for particular common warnings.

Also, the output is forced to use C-locale, as translated output
messages wouldn't be able to be read through grepping.

With this change there is no change in GCC's behaviour, but the Sun
Studio compiler won't be asked to use any flag it does not support
properly.
---

 configure |   26 ++++++++++++++++++--------
 1 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/configure b/configure
index 0fb0721..61055fd 100755
--- a/configure
+++ b/configure
@@ -222,7 +222,7 @@ Include the log file "$logfile" produced by configure as this will help
 solving the problem.
 EOF
     fi
-    rm -f $TMPC $TMPE $TMPH $TMPO $TMPS $TMPSH
+    rm -f $TMPC $TMPE $TMPH $TMPO $TMPS $TMPSH $TMPLOG $TMPRES
     exit 1
 }
 
@@ -419,21 +419,23 @@ add_extralibs(){
 
 check_cmd(){
     log "$@"
-    "$@" >> $logfile 2>&1
+    rm -f $TMPRES
+    ( "$@" 2>&1 && touch $TMPRES; ) | tee $TMPLOG >> $logfile
+    test -f $TMPRES
 }
 
 check_cc(){
     log check_cc "$@"
     cat > $TMPC
     log_file $TMPC
-    check_cmd $cc $CFLAGS "$@" -c -o $TMPO $TMPC
+    LC_ALL=C check_cmd $cc $CFLAGS "$@" -c -o $TMPO $TMPC
 }
 
 check_cpp(){
     log check_cpp "$@"
     cat > $TMPC
     log_file $TMPC
-    check_cmd $cc $CFLAGS "$@" -E -o $TMPO $TMPC
+    LC_ALL=C check_cmd $cc $CFLAGS "$@" -E -o $TMPO $TMPC
 }
 
 check_asm(){
@@ -441,7 +443,7 @@ check_asm(){
     name="$1"
     asm="$2"
     shift 2
-    check_cc "$@" <<EOF && enable $name || disable $name
+    LC_ALL=C check_cc "$@" <<EOF && enable $name || disable $name
 int foo(void){ asm volatile($asm); }
 EOF
 }
@@ -451,7 +453,7 @@ check_yasm(){
     echo "$1" > $TMPS
     log_file $TMPS
     shift 1
-    check_cmd $yasmexe $YASMFLAGS "$@" -o $TMPO $TMPS
+    LC_ALL=C check_cmd $yasmexe $YASMFLAGS "$@" -o $TMPO $TMPS
 }
 
 check_ld(){
@@ -462,14 +464,20 @@ check_ld(){
     for f; do
         test "${f}" = "${f#-l}" && flags="$flags $f" || libs="$libs $f"
     done
-    check_cmd $cc $LDFLAGS $flags -o $TMPE $TMPO $extralibs $libs
+    LC_ALL=C check_cmd $cc $LDFLAGS $flags -o $TMPE $TMPO $extralibs $libs
 }
 
 check_cflags(){
     log check_cflags "$@"
-    check_cc "$@" <<EOF && add_cflags "$@"
+    check_cc "$@" <<EOF || return
 int x;
 EOF
+
+    grep -qi "warning" $TMPLOG && return
+    grep -qi "illegal option" $TMPLOG && return
+    grep -qi "unrecognized" $TMPLOG && return
+
+    add_cflags "$@"
 }
 
 check_ldflags(){
@@ -1128,6 +1136,8 @@ TMPH="${TMPDIR1}/ffmpeg-conf-${RANDOM}-$$-${RANDOM}.h"
 TMPO="${TMPDIR1}/ffmpeg-conf-${RANDOM}-$$-${RANDOM}.o"
 TMPS="${TMPDIR1}/ffmpeg-conf-${RANDOM}-$$-${RANDOM}.S"
 TMPSH="${TMPDIR1}/ffmpeg-conf-${RANDOM}-$$-${RANDOM}.sh"
+TMPLOG="${TMPDIR1}/ffmpeg-conf-${RANDOM}-$$-${RANDOM}.log"
+TMPRES="${TMPDIR1}/ffmpeg-conf-${RANDOM}-$$-${RANDOM}.res"
 
 check_cflags -fasm
 check_cflags -std=c99