Adjust GCC warnings:

Better disable following warnings when cross-compiling with a gcc older
  than 3.0, to avoid warnings from third party system headers:

    -Wmissing-declarations
    -Wmissing-prototypes
    -Wunused
    -Wshadow

ares/m4/cares-compilers.m4

@@ -16,7 +16,7 @@
 #***************************************************************************
 
 # File version for 'aclocal' use. Keep it a single number.
-# serial 29
+# serial 32
 
 
 dnl CARES_CHECK_COMPILER
@@ -787,66 +787,96 @@ AC_DEFUN([CARES_SET_COMPILER_WARNING_OPTS], [
       GNU_C)
         #
         if test "$want_warnings" = "yes"; then
+          #
           dnl Do not enable -pedantic when cross-compiling with a gcc older
           dnl than 3.0, to avoid warnings from third party system headers.
           if test "x$cross_compiling" != "xyes" ||
             test "$compiler_num" -ge "300"; then
             tmp_CFLAGS="$tmp_CFLAGS -pedantic"
           fi
+          #
           dnl Set of options we believe *ALL* gcc versions support:
-          tmp_CFLAGS="$tmp_CFLAGS -Wall -W -Winline -Wnested-externs"
+          tmp_CFLAGS="$tmp_CFLAGS -Wall -W"
+          #
+          dnl Only gcc 1.4 or later
+          if test "$compiler_num" -ge "104"; then
             tmp_CFLAGS="$tmp_CFLAGS -Wpointer-arith -Wwrite-strings"
-          dnl -Wcast-align is a bit too annoying on all gcc versions ;-)
+            dnl If not cross-compiling with a gcc older than 3.0
-          dnl Do not enable some warnings, when cross-compiling with a gcc
-          dnl older than 3.0, triggered on third party system headers.
             if test "x$cross_compiling" != "xyes" ||
               test "$compiler_num" -ge "300"; then
+              tmp_CFLAGS="$tmp_CFLAGS -Wunused -Wshadow"
+            fi
+          fi
+          #
+          dnl Only gcc 2.7 or later
+          if test "$compiler_num" -ge "207"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Winline -Wnested-externs"
+            dnl If not cross-compiling with a gcc older than 3.0
+            if test "x$cross_compiling" != "xyes" ||
+              test "$compiler_num" -ge "300"; then
+              tmp_CFLAGS="$tmp_CFLAGS -Wmissing-declarations"
               tmp_CFLAGS="$tmp_CFLAGS -Wmissing-prototypes"
             fi
-          if test "$compiler_num" -ge "207"; then
-            dnl gcc 2.7 or later
-            tmp_CFLAGS="$tmp_CFLAGS -Wmissing-declarations"
           fi
-          if test "$compiler_num" -gt "295"; then
+          #
-            dnl only if the compiler is newer than 2.95 since we got lots of
+          dnl Only gcc 2.95 or later
-            dnl "`_POSIX_C_SOURCE' is not defined" in system headers with
+          if test "$compiler_num" -ge "295"; then
-            dnl gcc 2.95.4 on FreeBSD 4.9!
+            tmp_CFLAGS="$tmp_CFLAGS -Wno-long-long"
-            tmp_CFLAGS="$tmp_CFLAGS -Wno-long-long -Wno-multichar -Wshadow"
-            tmp_CFLAGS="$tmp_CFLAGS -Wsign-compare -Wundef"
           fi
+          #
+          dnl Only gcc 2.96 or later
           if test "$compiler_num" -ge "296"; then
-            dnl gcc 2.96 or later
             tmp_CFLAGS="$tmp_CFLAGS -Wfloat-equal"
+            tmp_CFLAGS="$tmp_CFLAGS -Wno-multichar -Wsign-compare"
+            dnl -Wundef used only if gcc is 2.96 or later since we get
+            dnl lots of "`_POSIX_C_SOURCE' is not defined" in system
+            dnl headers with gcc 2.95.4 on FreeBSD 4.9
+            tmp_CFLAGS="$tmp_CFLAGS -Wundef"
           fi
-          if test "$compiler_num" -gt "296"; then
+          #
-            dnl this option does not exist in 2.96
+          dnl Only gcc 2.97 or later
+          if test "$compiler_num" -ge "297"; then
             tmp_CFLAGS="$tmp_CFLAGS -Wno-format-nonliteral"
           fi
+          #
+          dnl Only gcc 3.0 or later
+          if test "$compiler_num" -ge "300"; then
             dnl -Wunreachable-code seems totally unreliable on my gcc 3.3.2 on
             dnl on i686-Linux as it gives us heaps with false positives.
             dnl Also, on gcc 4.0.X it is totally unbearable and complains all
             dnl over making it unusable for generic purposes. Let's not use it.
+            tmp_CFLAGS="$tmp_CFLAGS"
+          fi
+          #
+          dnl Only gcc 3.3 or later
           if test "$compiler_num" -ge "303"; then
-            dnl gcc 3.3 and later
             tmp_CFLAGS="$tmp_CFLAGS -Wendif-labels -Wstrict-prototypes"
           fi
+          #
+          dnl Only gcc 3.4 or later
           if test "$compiler_num" -ge "304"; then
-            dnl gcc 3.4 and later
             tmp_CFLAGS="$tmp_CFLAGS -Wdeclaration-after-statement"
           fi
+          #
         fi
         #
         dnl Do not issue warnings for code in system include paths.
         if test "$compiler_num" -ge "300"; then
-          dnl gcc 3.0 and later
           tmp_CFLAGS="$tmp_CFLAGS -Wno-system-headers"
         else
-          dnl Disable some warnings, when cross-compiling with a gcc
+          dnl When cross-compiling with a gcc older than 3.0, disable
-          dnl older than 3.0, triggered on third party system headers.
+          dnl some warnings triggered on third party system headers.
           if test "x$cross_compiling" = "xyes"; then
-            tmp_CFLAGS="$tmp_CFLAGS -Wno-missing-prototypes"
+            if test "$compiler_num" -ge "104"; then
+              dnl gcc 1.4 or later
               tmp_CFLAGS="$tmp_CFLAGS -Wno-unused -Wno-shadow"
             fi
+            if test "$compiler_num" -ge "207"; then
+              dnl gcc 2.7 or later
+              tmp_CFLAGS="$tmp_CFLAGS -Wno-missing-declarations"
+              tmp_CFLAGS="$tmp_CFLAGS -Wno-missing-prototypes"
+            fi
+          fi
         fi
         ;;
         #

m4/curl-compilers.m4

@@ -22,7 +22,7 @@
 #***************************************************************************
 
 # File version for 'aclocal' use. Keep it a single number.
-# serial 28
+# serial 31
 
 
 dnl CURL_CHECK_COMPILER
@@ -793,66 +793,96 @@ AC_DEFUN([CURL_SET_COMPILER_WARNING_OPTS], [
       GNU_C)
         #
         if test "$want_warnings" = "yes"; then
+          #
           dnl Do not enable -pedantic when cross-compiling with a gcc older
           dnl than 3.0, to avoid warnings from third party system headers.
           if test "x$cross_compiling" != "xyes" ||
             test "$compiler_num" -ge "300"; then
             tmp_CFLAGS="$tmp_CFLAGS -pedantic"
           fi
+          #
           dnl Set of options we believe *ALL* gcc versions support:
-          tmp_CFLAGS="$tmp_CFLAGS -Wall -W -Winline -Wnested-externs"
+          tmp_CFLAGS="$tmp_CFLAGS -Wall -W"
+          #
+          dnl Only gcc 1.4 or later
+          if test "$compiler_num" -ge "104"; then
             tmp_CFLAGS="$tmp_CFLAGS -Wpointer-arith -Wwrite-strings"
-          dnl -Wcast-align is a bit too annoying on all gcc versions ;-)
+            dnl If not cross-compiling with a gcc older than 3.0
-          dnl Do not enable some warnings, when cross-compiling with a gcc
-          dnl older than 3.0, triggered on third party system headers.
             if test "x$cross_compiling" != "xyes" ||
               test "$compiler_num" -ge "300"; then
+              tmp_CFLAGS="$tmp_CFLAGS -Wunused -Wshadow"
+            fi
+          fi
+          #
+          dnl Only gcc 2.7 or later
+          if test "$compiler_num" -ge "207"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Winline -Wnested-externs"
+            dnl If not cross-compiling with a gcc older than 3.0
+            if test "x$cross_compiling" != "xyes" ||
+              test "$compiler_num" -ge "300"; then
+              tmp_CFLAGS="$tmp_CFLAGS -Wmissing-declarations"
               tmp_CFLAGS="$tmp_CFLAGS -Wmissing-prototypes"
             fi
-          if test "$compiler_num" -ge "207"; then
-            dnl gcc 2.7 or later
-            tmp_CFLAGS="$tmp_CFLAGS -Wmissing-declarations"
           fi
-          if test "$compiler_num" -gt "295"; then
+          #
-            dnl only if the compiler is newer than 2.95 since we got lots of
+          dnl Only gcc 2.95 or later
-            dnl "`_POSIX_C_SOURCE' is not defined" in system headers with
+          if test "$compiler_num" -ge "295"; then
-            dnl gcc 2.95.4 on FreeBSD 4.9!
+            tmp_CFLAGS="$tmp_CFLAGS -Wno-long-long"
-            tmp_CFLAGS="$tmp_CFLAGS -Wno-long-long -Wno-multichar -Wshadow"
-            tmp_CFLAGS="$tmp_CFLAGS -Wsign-compare -Wundef"
           fi
+          #
+          dnl Only gcc 2.96 or later
           if test "$compiler_num" -ge "296"; then
-            dnl gcc 2.96 or later
             tmp_CFLAGS="$tmp_CFLAGS -Wfloat-equal"
+            tmp_CFLAGS="$tmp_CFLAGS -Wno-multichar -Wsign-compare"
+            dnl -Wundef used only if gcc is 2.96 or later since we get
+            dnl lots of "`_POSIX_C_SOURCE' is not defined" in system
+            dnl headers with gcc 2.95.4 on FreeBSD 4.9
+            tmp_CFLAGS="$tmp_CFLAGS -Wundef"
           fi
-          if test "$compiler_num" -gt "296"; then
+          #
-            dnl this option does not exist in 2.96
+          dnl Only gcc 2.97 or later
+          if test "$compiler_num" -ge "297"; then
             tmp_CFLAGS="$tmp_CFLAGS -Wno-format-nonliteral"
           fi
+          #
+          dnl Only gcc 3.0 or later
+          if test "$compiler_num" -ge "300"; then
             dnl -Wunreachable-code seems totally unreliable on my gcc 3.3.2 on
             dnl on i686-Linux as it gives us heaps with false positives.
             dnl Also, on gcc 4.0.X it is totally unbearable and complains all
             dnl over making it unusable for generic purposes. Let's not use it.
+            tmp_CFLAGS="$tmp_CFLAGS"
+          fi
+          #
+          dnl Only gcc 3.3 or later
           if test "$compiler_num" -ge "303"; then
-            dnl gcc 3.3 and later
             tmp_CFLAGS="$tmp_CFLAGS -Wendif-labels -Wstrict-prototypes"
           fi
+          #
+          dnl Only gcc 3.4 or later
           if test "$compiler_num" -ge "304"; then
-            dnl gcc 3.4 and later
             tmp_CFLAGS="$tmp_CFLAGS -Wdeclaration-after-statement"
           fi
+          #
         fi
         #
         dnl Do not issue warnings for code in system include paths.
         if test "$compiler_num" -ge "300"; then
-          dnl gcc 3.0 and later
           tmp_CFLAGS="$tmp_CFLAGS -Wno-system-headers"
         else
-          dnl Disable some warnings, when cross-compiling with a gcc
+          dnl When cross-compiling with a gcc older than 3.0, disable
-          dnl older than 3.0, triggered on third party system headers.
+          dnl some warnings triggered on third party system headers.
           if test "x$cross_compiling" = "xyes"; then
-            tmp_CFLAGS="$tmp_CFLAGS -Wno-missing-prototypes"
+            if test "$compiler_num" -ge "104"; then
+              dnl gcc 1.4 or later
               tmp_CFLAGS="$tmp_CFLAGS -Wno-unused -Wno-shadow"
             fi
+            if test "$compiler_num" -ge "207"; then
+              dnl gcc 2.7 or later
+              tmp_CFLAGS="$tmp_CFLAGS -Wno-missing-declarations"
+              tmp_CFLAGS="$tmp_CFLAGS -Wno-missing-prototypes"
+            fi
+          fi
         fi
         ;;
         #