Merge r1812263, r1812301 from trunk:

Fix maintainer mode with GCC/Clang.

Setting -Wstrict-prototypes in combination
with -Werror leads to compiler errors during
configure checks (autoconf generates incomplete
prototypes).

Adding -Wno-error=strict-prototypes lets the
compiler tolerate those.

Possible future enhancement: remember such
"configure time only" flags and remove them
from CFLAGS before generating our build time
files (Makefile, config_vars.mk etc.), so that
the full -Werror is in place during building.


Follow up to r1812263.

As suggested by Joe, add --maintainer/debugger-mode's CFLAGS in
NOTEST_CFLAGS to avoid interractions with autoconf's AC_LANG_PROGRAM.

APACHE_ADD_GCC_CFLAG now also forces -Wno-strict-prototypes for -Werror
to work despite AC_LANG_PROGRAM generating this warning by itself.


Submitted by: rjung, ylavic
Reviewed by: ylavic, rjung, jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1812437 13f79535-47bb-0310-9956-ffa450edef68

STATUS

@@ -117,21 +117,6 @@ RELEASE SHOWSTOPPERS:
 PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
   [ start all new proposals below, under PATCHES PROPOSED. ]
 
-  *) configure.in: Fix maintainer mode with GCC/Clang.
-     Setting -Wstrict-prototypes in combination with -Werror leads to compiler
-     errors during configure checks (autoconf generates incomplete prototypes).
-     As suggested by Joe, add --maintainer/debugger-mode's CFLAGS in
-     NOTEST_CFLAGS to avoid interractions with autoconf's AC_LANG_PROGRAM.
-     APACHE_ADD_GCC_CFLAG now also forces -Wno-strict-prototypes for -Werror
-     to work despite AC_LANG_PROGRAM generating this warning by itself.
-     trunk patch: http://svn.apache.org/r1812263
-                  http://svn.apache.org/r1812301
-     2.4.x patch: svn merge -c 1812263,1812301 ^/httpd/httpd/trunk .
-     +1: ylavic, rjung, jim
-     ylavic: if the below mod_journald proposal gets accepted, it will
-             also need a backport of r1812339, otherwise maintainer
-             mode builds will fail due to -Werror.
-
 
 
 PATCHES PROPOSED TO BACKPORT FROM TRUNK:

acinclude.m4

@@ -726,22 +726,26 @@ YES_IS_DEFINED
 ])
 
 dnl
-dnl APACHE_ADD_GCC_CFLAGS
+dnl APACHE_ADD_GCC_CFLAG
 dnl
-dnl Check if compiler is gcc and supports flag. If yes, add to CFLAGS.
+dnl Check if compiler is gcc and supports flag. If yes, add to NOTEST_CFLAGS.
+dnl NOTEST_CFLAGS is merged lately, thus it won't accumulate in CFLAGS here.
+dnl Also, AC_LANG_PROGRAM() itself is known to trigger [-Wstrict-prototypes]
+dnl with some autoconf versions, so we force -Wno-strict-prototypes for the
+dnl check to avoid spurious failures when adding flags like -Werror.
 dnl
 AC_DEFUN([APACHE_ADD_GCC_CFLAG], [
   define([ap_gcc_ckvar], [ac_cv_gcc_]translit($1, [-:.=], [____]))
   if test "$GCC" = "yes"; then
     AC_CACHE_CHECK([whether gcc accepts $1], ap_gcc_ckvar, [
       save_CFLAGS="$CFLAGS"
-      CFLAGS="$CFLAGS $1"
+      CFLAGS="$CFLAGS $1 -Wno-strict-prototypes"
       AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
         [ap_gcc_ckvar=yes], [ap_gcc_ckvar=no])
       CFLAGS="$save_CFLAGS"
     ])
     if test "$]ap_gcc_ckvar[" = "yes" ; then
-       APR_ADDTO(CFLAGS,[$1])
+       APR_ADDTO(NOTEST_CFLAGS,[$1])
     fi
   fi
   undefine([ap_gcc_ckvar])

configure.in

@@ -593,17 +593,21 @@ AC_ARG_ENABLE(load-all-modules,APACHE_HELP_STRING(--enable-load-all-modules,Load
 AC_ARG_ENABLE(maintainer-mode,APACHE_HELP_STRING(--enable-maintainer-mode,Turn on debugging and compile time warnings and load all compiled modules),
 [
   if test "$enableval" = "yes"; then
-    APR_ADDTO(CPPFLAGS, -DAP_DEBUG)
+    APR_ADDTO(NOTEST_CPPFLAGS, -DAP_DEBUG)
     if test "$GCC" = "yes"; then
-      APR_ADDTO(CFLAGS,[-Wall -Wmissing-prototypes -Wstrict-prototypes -Wmissing-declarations -Wpointer-arith])
       APACHE_ADD_GCC_CFLAG([-std=c89])
       APACHE_ADD_GCC_CFLAG([-Werror])
+      APACHE_ADD_GCC_CFLAG([-Wall])
+      APACHE_ADD_GCC_CFLAG([-Wstrict-prototypes])
+      APACHE_ADD_GCC_CFLAG([-Wmissing-prototypes])
+      APACHE_ADD_GCC_CFLAG([-Wmissing-declarations])
       APACHE_ADD_GCC_CFLAG([-Wdeclaration-after-statement])
+      APACHE_ADD_GCC_CFLAG([-Wpointer-arith])
       APACHE_ADD_GCC_CFLAG([-Wformat])
       APACHE_ADD_GCC_CFLAG([-Wformat-security])
       APACHE_ADD_GCC_CFLAG([-Wunused])
     elif test "$AIX_XLC" = "yes"; then
-      APR_ADDTO(CFLAGS,-qfullpath -qinitauto=FE -qcheck=all -qinfo=pro)
+      APR_ADDTO(NOTEST_CFLAGS,-qfullpath -qinitauto=FE -qcheck=all -qinfo=pro)
     fi
     if test "x$enable_load_all_modules" = "x"; then
       LOAD_ALL_MODULES=yes
@@ -619,16 +623,21 @@ AC_ARG_ENABLE(maintainer-mode,APACHE_HELP_STRING(--enable-maintainer-mode,Turn o
 AC_ARG_ENABLE(debugger-mode,APACHE_HELP_STRING(--enable-debugger-mode,Turn on debugging and compile time warnings and turn off optimization),
 [
   if test "$enableval" = "yes"; then
-    APR_ADDTO(CPPFLAGS, -DAP_DEBUG)
+    APR_ADDTO(NOTEST_CPPFLAGS, -DAP_DEBUG)
     if test "$GCC" = "yes"; then
-      APR_ADDTO(CFLAGS,[-Wall -Wmissing-prototypes -Wstrict-prototypes -Wmissing-declarations -Wpointer-arith -O0])
+      APACHE_ADD_GCC_CFLAG([-O0])
+      APACHE_ADD_GCC_CFLAG([-Wall])
+      APACHE_ADD_GCC_CFLAG([-Wstrict-prototypes])
+      APACHE_ADD_GCC_CFLAG([-Wmissing-prototypes])
+      APACHE_ADD_GCC_CFLAG([-Wmissing-declarations])
       APACHE_ADD_GCC_CFLAG([-Wdeclaration-after-statement])
       APACHE_ADD_GCC_CFLAG([-Werror=declaration-after-statement])
+      APACHE_ADD_GCC_CFLAG([-Wpointer-arith])
       APACHE_ADD_GCC_CFLAG([-Wformat])
       APACHE_ADD_GCC_CFLAG([-Wformat-security])
       APACHE_ADD_GCC_CFLAG([-Werror=format-security])
     elif test "$AIX_XLC" = "yes"; then
-      APR_ADDTO(CFLAGS,-qfullpath -qinitauto=FE -qcheck=all -qinfo=pro)
+      APR_ADDTO(NOTEST_CFLAGS,-qfullpath -qinitauto=FE -qcheck=all -qinfo=pro)
     fi
   fi
 ])dnl
@@ -810,10 +819,10 @@ AC_MSG_NOTICE([Restore user-defined environment settings...])
 AC_MSG_NOTICE([])
 
 APACHE_CONF_SEL_CC=${CC}
-APACHE_CONF_SEL_CFLAGS=${CFLAGS}
+APACHE_CONF_SEL_CFLAGS="${CFLAGS} ${EXTRA_CFLAGS} ${NOTEST_CFLAGS}"
-APACHE_CONF_SEL_LDFLAGS=${LDFLAGS}
+APACHE_CONF_SEL_CPPFLAGS="${CPPFLAGS} ${EXTRA_CPPFLAGS} ${NOTEST_CPPFLAGS}"
-APACHE_CONF_SEL_LIBS=${LIBS}
+APACHE_CONF_SEL_LDFLAGS="${LDFLAGS} ${EXTRA_LDFLAGS} ${NOTEST_LDFLAGS}"
-APACHE_CONF_SEL_CPPFLAGS=${CPPFLAGS}
+APACHE_CONF_SEL_LIBS="${LIBS} ${EXTRA_LIBS} ${NOTEST_LIBS}"
 APACHE_CONF_SEL_CPP=${CPP}
 
 APR_RESTORE_THE_ENVIRONMENT(CPPFLAGS, EXTRA_)
@@ -879,8 +888,8 @@ AC_MSG_NOTICE([summary of build options:
     Install prefix: ${prefix}
     C compiler:     ${APACHE_CONF_SEL_CC}
     CFLAGS:         ${APACHE_CONF_SEL_CFLAGS}
+    CPPFLAGS:       ${APACHE_CONF_SEL_CPPFLAGS}
     LDFLAGS:        ${APACHE_CONF_SEL_LDFLAGS}
     LIBS:           ${APACHE_CONF_SEL_LIBS}
-    CPPFLAGS:       ${APACHE_CONF_SEL_CPPFLAGS}
     C preprocessor: ${APACHE_CONF_SEL_CPP}
 ])