wrap some autoconf macros in AC_CACHE_CHECK

This allows skipping/overriding the OSSH_CHECK_CFLAG_COMPILE and
OSSH_CHECK_CFLAG_LINK macros used to discover supported compiler
or linker flags. E.g.

  $ ./configure ossh_cv_cflag__fzero_call_used_regs_used=no
  [...]
  checking if cc supports compile flag -ftrapv and linking succeeds... yes
  checking if cc supports compile flag -fzero-call-used-regs=used and linking succeeds... (cached) no
  checking if cc supports compile flag -ftrivial-auto-var-init=zero... yes

Patch from Colin Watson, ok dtucker@

diff --git a/m4/openssh.m4 b/m4/openssh.m4
index 176a8d1c9282f4ea7d5475c210eb82aba107cbc8..f420146f14426706a2193034b71d55348c32b51a 100644 (file)
--- a/m4/openssh.m4
+++ b/m4/openssh.m4
@@ -62,7 +62,8 @@ dnl Check that $CC accepts a flag 'check_flag'. If it is supported append
 dnl 'define_flag' to $CFLAGS. If 'define_flag' is not specified, then append
 dnl 'check_flag'.
 AC_DEFUN([OSSH_CHECK_CFLAG_COMPILE], [{
-       AC_MSG_CHECKING([if $CC supports compile flag $1])
+  ossh_cache_var=AS_TR_SH([ossh_cv_cflag_$1])
+  AC_CACHE_CHECK([if $CC supports compile flag $1], [$ossh_cache_var], [
        saved_CFLAGS="$CFLAGS"
        CFLAGS="$CFLAGS $WERROR $1"
        _define_flag="$2"
@@ -71,22 +72,23 @@ AC_DEFUN([OSSH_CHECK_CFLAG_COMPILE], [{
                [
 if $ac_cv_path_EGREP -i "unrecognized option|warning.*ignored" conftest.err >/dev/null
 then
-               AC_MSG_RESULT([no])
+               eval "$ossh_cache_var=no"
                CFLAGS="$saved_CFLAGS"
 else
                dnl If we are compiling natively, try running the program.
                AC_RUN_IFELSE([OSSH_COMPILER_FLAG_TEST_PROGRAM],
-                       [ AC_MSG_RESULT([yes])
+                       [ eval "$ossh_cache_var=yes"
                          CFLAGS="$saved_CFLAGS $_define_flag" ],
-                       [ AC_MSG_RESULT([no, fails at run time])
+                       [ eval "$ossh_cache_var='no, fails at run time'"
                          CFLAGS="$saved_CFLAGS" ],
-                       [ AC_MSG_RESULT([yes])
+                       [ eval "$ossh_cache_var=yes"
                          CFLAGS="$saved_CFLAGS $_define_flag" ],
                )
 fi],
-               [ AC_MSG_RESULT([no])
+               [ eval "$ossh_cache_var=no"
                  CFLAGS="$saved_CFLAGS" ]
        )
+  ])
 }])
 
 dnl OSSH_CHECK_CFLAG_LINK(check_flag[, define_flag])
@@ -94,7 +96,8 @@ dnl Check that $CC accepts a flag 'check_flag'. If it is supported append
 dnl 'define_flag' to $CFLAGS. If 'define_flag' is not specified, then append
 dnl 'check_flag'.
 AC_DEFUN([OSSH_CHECK_CFLAG_LINK], [{
-       AC_MSG_CHECKING([if $CC supports compile flag $1 and linking succeeds])
+  ossh_cache_var=AS_TR_SH([ossh_cv_cflag_$1])
+  AC_CACHE_CHECK([if $CC supports compile flag $1 and linking succeeds], [$ossh_cache_var], [
        saved_CFLAGS="$CFLAGS"
        CFLAGS="$CFLAGS $WERROR $1"
        _define_flag="$2"
@@ -103,22 +106,23 @@ AC_DEFUN([OSSH_CHECK_CFLAG_LINK], [{
                [
 if $ac_cv_path_EGREP -i "unrecognized option|warning.*ignored" conftest.err >/dev/null
 then
-               AC_MSG_RESULT([no])
+               eval "$ossh_cache_var=no"
                CFLAGS="$saved_CFLAGS"
 else
                dnl If we are compiling natively, try running the program.
                AC_RUN_IFELSE([OSSH_COMPILER_FLAG_TEST_PROGRAM],
-                       [ AC_MSG_RESULT([yes])
+                       [ eval "$ossh_cache_var=yes"
                          CFLAGS="$saved_CFLAGS $_define_flag" ],
-                       [ AC_MSG_RESULT([no, fails at run time])
+                       [ eval "$ossh_cache_var='no, fails at run time'"
                          CFLAGS="$saved_CFLAGS" ],
-                       [ AC_MSG_RESULT([yes])
+                       [ eval "$ossh_cache_var=yes"
                          CFLAGS="$saved_CFLAGS $_define_flag" ],
                )
 fi],
-               [ AC_MSG_RESULT([no])
+               [ eval "$ossh_cache_var=no"
                  CFLAGS="$saved_CFLAGS" ]
        )
+  ])
 }])
 
 dnl OSSH_CHECK_LDFLAG_LINK(check_flag[, define_flag])
@@ -126,7 +130,8 @@ dnl Check that $LD accepts a flag 'check_flag'. If it is supported append
 dnl 'define_flag' to $LDFLAGS. If 'define_flag' is not specified, then append
 dnl 'check_flag'.
 AC_DEFUN([OSSH_CHECK_LDFLAG_LINK], [{
-       AC_MSG_CHECKING([if $LD supports link flag $1])
+  ossh_cache_var=AS_TR_SH([ossh_cv_ldflag_$1])
+  AC_CACHE_CHECK([if $LD supports link flag $1], [$ossh_cache_var], [
        saved_LDFLAGS="$LDFLAGS"
        LDFLAGS="$LDFLAGS $WERROR $1"
        _define_flag="$2"
@@ -135,22 +140,23 @@ AC_DEFUN([OSSH_CHECK_LDFLAG_LINK], [{
                [
 if $ac_cv_path_EGREP -i "unrecognized option|warning.*ignored" conftest.err >/dev/null
 then
-                 AC_MSG_RESULT([no])
+                 eval "$ossh_cache_var=no"
                  LDFLAGS="$saved_LDFLAGS"
 else
                  dnl If we are compiling natively, try running the program.
                  AC_RUN_IFELSE([OSSH_COMPILER_FLAG_TEST_PROGRAM],
-                       [ AC_MSG_RESULT([yes])
+                       [ eval "$ossh_cache_var=yes"
                          LDFLAGS="$saved_LDFLAGS $_define_flag" ],
-                       [ AC_MSG_RESULT([no, fails at run time])
+                       [ eval "$ossh_cache_var='no, fails at run time'"
                          LDFLAGS="$saved_LDFLAGS" ],
-                       [ AC_MSG_RESULT([yes])
+                       [ eval "$ossh_cache_var=yes"
                          LDFLAGS="$saved_LDFLAGS $_define_flag" ]
                  )
 fi             ],
-               [ AC_MSG_RESULT([no])
+               [ eval "$ossh_cache_var=no"
                  LDFLAGS="$saved_LDFLAGS" ]
        )
+  ])
 }])
 
 dnl OSSH_CHECK_HEADER_FOR_FIELD(field, header, symbol)