Adjust configure to use "+Olibmerrno" with HP-UX C compiler, if possible.

This is reported to be necessary on some versions of that OS.  In service
of this, cause PGAC_PROG_CC_CFLAGS_OPT to reject switches that result in
compiler warnings, since on yet other versions of that OS, the switch does
nothing except provoke a warning.

Report and patch by Ibrar Ahmed, further tweaking by me.

3 files changed, 94 insertions, 0 deletions

diff --git a/config/c-compiler.m4 b/config/c-compiler.m4
index 9c069f4c92..9398ca6c47 100644
--- a/config/c-compiler.m4
+++ b/config/c-compiler.m4
@@ -130,9 +130,12 @@ AC_DEFUN([PGAC_PROG_CC_CFLAGS_OPT],
 AC_CACHE_CHECK([whether $CC supports $1], [Ac_cachevar],
 [pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS $1"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
 _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
                    [Ac_cachevar=yes],
                    [Ac_cachevar=no])
+ac_c_werror_flag=$ac_save_c_werror_flag
 CFLAGS="$pgac_save_CFLAGS"])
 if test x"$Ac_cachevar" = x"yes"; then
   CFLAGS="$CFLAGS $1"
diff --git a/configure b/configure
index 3b23c46293..e73315721b 100755
--- a/configure
+++ b/configure
@@ -4010,6 +4010,8 @@ if test "${pgac_cv_prog_cc_cflags__Wdeclaration_after_statement+set}" = set; the
 else
   pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS -Wdeclaration-after-statement"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -4052,6 +4054,7 @@ sed 's/^/| /' conftest.$ac_ext >&5
 fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
 CFLAGS="$pgac_save_CFLAGS"
 fi
 { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__Wdeclaration_after_statement" >&5
@@ -4067,6 +4070,8 @@ if test "${pgac_cv_prog_cc_cflags__Wendif_labels+set}" = set; then
 else
   pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS -Wendif-labels"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -4109,6 +4114,7 @@ sed 's/^/| /' conftest.$ac_ext >&5
 fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
 CFLAGS="$pgac_save_CFLAGS"
 fi
 { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__Wendif_labels" >&5
@@ -4125,6 +4131,8 @@ if test "${pgac_cv_prog_cc_cflags__Wformat_security+set}" = set; then
 else
   pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS -Wformat-security"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -4167,6 +4175,7 @@ sed 's/^/| /' conftest.$ac_ext >&5
 fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
 CFLAGS="$pgac_save_CFLAGS"
 fi
 { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__Wformat_security" >&5
@@ -4183,6 +4192,8 @@ if test "${pgac_cv_prog_cc_cflags__fno_strict_aliasing+set}" = set; then
 else
   pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS -fno-strict-aliasing"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -4225,6 +4236,7 @@ sed 's/^/| /' conftest.$ac_ext >&5
 fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
 CFLAGS="$pgac_save_CFLAGS"
 fi
 { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__fno_strict_aliasing" >&5
@@ -4241,6 +4253,8 @@ if test "${pgac_cv_prog_cc_cflags__fwrapv+set}" = set; then
 else
   pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS -fwrapv"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -4283,6 +4297,7 @@ sed 's/^/| /' conftest.$ac_ext >&5
 fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
 CFLAGS="$pgac_save_CFLAGS"
 fi
 { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__fwrapv" >&5
@@ -4301,6 +4316,8 @@ if test "${pgac_cv_prog_cc_cflags__mp1+set}" = set; then
 else
   pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS -mp1"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -4343,6 +4360,7 @@ sed 's/^/| /' conftest.$ac_ext >&5
 fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
 CFLAGS="$pgac_save_CFLAGS"
 fi
 { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__mp1" >&5
@@ -4359,6 +4377,8 @@ if test "${pgac_cv_prog_cc_cflags__fno_strict_aliasing+set}" = set; then
 else
   pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS -fno-strict-aliasing"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -4401,6 +4421,7 @@ sed 's/^/| /' conftest.$ac_ext >&5
 fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
 CFLAGS="$pgac_save_CFLAGS"
 fi
 { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__fno_strict_aliasing" >&5
@@ -4418,6 +4439,8 @@ if test "${pgac_cv_prog_cc_cflags__qnoansialias+set}" = set; then
 else
   pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS -qnoansialias"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -4460,6 +4483,7 @@ sed 's/^/| /' conftest.$ac_ext >&5
 fi
 
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
 CFLAGS="$pgac_save_CFLAGS"
 fi
 { $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__qnoansialias" >&5
@@ -4468,6 +4492,69 @@ if test x"$pgac_cv_prog_cc_cflags__qnoansialias" = x"yes"; then
   CFLAGS="$CFLAGS -qnoansialias"
 fi
 
+elif test "$PORTNAME" = "hpux"; then
+  # On some versions of HP-UX, libm functions do not set errno by default.
+  # Fix that by using +Olibmerrno if the compiler recognizes it.
+  { $as_echo "$as_me:$LINENO: checking whether $CC supports +Olibmerrno" >&5
+$as_echo_n "checking whether $CC supports +Olibmerrno... " >&6; }
+if test "${pgac_cv_prog_cc_cflags_pOlibmerrno+set}" = set; then
+  $as_echo_n "(cached) " >&6
+else
+  pgac_save_CFLAGS=$CFLAGS
+CFLAGS="$pgac_save_CFLAGS +Olibmerrno"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
+$as_echo "$ac_try_echo") >&5
+  (eval "$ac_compile") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest.$ac_objext; then
+  pgac_cv_prog_cc_cflags_pOlibmerrno=yes
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	pgac_cv_prog_cc_cflags_pOlibmerrno=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
+CFLAGS="$pgac_save_CFLAGS"
+fi
+{ $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags_pOlibmerrno" >&5
+$as_echo "$pgac_cv_prog_cc_cflags_pOlibmerrno" >&6; }
+if test x"$pgac_cv_prog_cc_cflags_pOlibmerrno" = x"yes"; then
+  CFLAGS="$CFLAGS +Olibmerrno"
+fi
+
 fi
 
 # supply -g if --enable-debug
diff --git a/configure.in b/configure.in
index 76c1a887a3..a752618bf5 100644
--- a/configure.in
+++ b/configure.in
@@ -445,6 +445,10 @@ elif test "$ICC" = yes; then
 elif test "$PORTNAME" = "aix"; then
   # AIX's xlc has to have strict aliasing turned off too
   PGAC_PROG_CC_CFLAGS_OPT([-qnoansialias])
+elif test "$PORTNAME" = "hpux"; then
+  # On some versions of HP-UX, libm functions do not set errno by default.
+  # Fix that by using +Olibmerrno if the compiler recognizes it.
+  PGAC_PROG_CC_CFLAGS_OPT([+Olibmerrno])
 fi
 
 # supply -g if --enable-debug