1 files changed, 32 insertions, 7 deletions

diff --git a/configure b/configure
index b9a0b2741e..97b69a0d73 100755
--- a/configure
+++ b/configure
@@ -27,16 +27,40 @@ printf " '%s'" "$0" "$@" >> config.log
 echo >> config.log
 echo "#" >> config.log
 
+do_cc() {
+    # Run the compiler, capturing its output to the log.
+    echo $cc "$@" >> config.log
+    $cc "$@" >> config.log 2>&1 || return $?
+    # Test passed. If this is an --enable-werror build, rerun
+    # the test with -Werror and bail out if it fails. This
+    # makes warning-generating-errors in configure test code
+    # obvious to developers.
+    if test "$werror" != "yes"; then
+        return 0
+    fi
+    # Don't bother rerunning the compile if we were already using -Werror
+    case "$*" in
+        *-Werror*)
+           return 0
+        ;;
+    esac
+    echo $cc -Werror "$@" >> config.log
+    $cc -Werror "$@" >> config.log 2>&1 && return $?
+    echo "ERROR: configure test passed without -Werror but failed with -Werror."
+    echo "This is probably a bug in the configure script. The failing command"
+    echo "will be at the bottom of config.log."
+    echo "You can run configure with --disable-werror to bypass this check."
+    exit 1
+}
+
 compile_object() {
-  echo $cc $QEMU_CFLAGS -c -o $TMPO $TMPC >> config.log
-  $cc $QEMU_CFLAGS -c -o $TMPO $TMPC >> config.log 2>&1
+  do_cc $QEMU_CFLAGS -c -o $TMPO $TMPC
 }
 
 compile_prog() {
   local_cflags="$1"
   local_ldflags="$2"
-  echo $cc $QEMU_CFLAGS $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags >> config.log
-  $cc $QEMU_CFLAGS $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags >> config.log 2>&1
+  do_cc $QEMU_CFLAGS $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags
 }
 
 # symbolically link $1 to $2.  Portable version of "ln -sf".
@@ -935,6 +959,7 @@ sparc64-softmmu \
 s390x-softmmu \
 xtensa-softmmu \
 xtensaeb-softmmu \
+unicore32-softmmu \
 "
 fi
 # the following are Linux specific
@@ -2231,7 +2256,7 @@ cat > $TMPC <<EOF
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <unistd.h>
-int main(void) { return preadv == preadv; }
+int main(void) { return preadv(0, 0, 0, 0); }
 EOF
 preadv=no
 if compile_prog "" "" ; then
@@ -2527,7 +2552,7 @@ int main(void)
      * warning but not an error, and will proceed to fail the
      * qemu compile where we compile with -Werror.)
      */
-    return epoll_create1 == epoll_create1;
+    return (int)(uintptr_t)&epoll_create1;
 }
 EOF
 if compile_prog "" "" ; then
@@ -2920,7 +2945,7 @@ has_environ=no
 cat > $TMPC << EOF
 #include <unistd.h>
 int main(void) {
-    environ = environ;
+    environ = 0;
     return 0;
 }
 EOF