configure: use cpp -P when needed

Since gcc 5, the processor output can get split up on multiple lines
that made the configure script fail to figure out values from
definitions. The fix is to use cpp -P, and this fix now first checks if
cpp -P is necessary and then if cpp -P works before it uses that to
extract defined values.

Fixes #719
This commit is contained in:
Daniel Stenberg 2016-03-18 16:26:05 +01:00
parent 7e312bdfdd
commit ecf953432d

View File

@ -20,7 +20,6 @@
#
#***************************************************************************
dnl CURL_CHECK_DEF (SYMBOL, [INCLUDES], [SILENT])
dnl -------------------------------------------------
dnl Use the C preprocessor to find out if the given object-style symbol
@ -31,6 +30,10 @@ dnl result in a set of double-quoted strings the returned expansion will
dnl actually be a single double-quoted string concatenating all them.
AC_DEFUN([CURL_CHECK_DEF], [
AC_REQUIRE([CURL_CPP_P])dnl
OLDCPPFLAGS=$CPPFLAGS
# CPPPFLAGS comes from CURL_CPP_P
CPPFLAGS="$CPPPFLAGS"
AS_VAR_PUSHDEF([ac_HaveDef], [curl_cv_have_def_$1])dnl
AS_VAR_PUSHDEF([ac_Def], [curl_cv_def_$1])dnl
if test -z "$SED"; then
@ -67,6 +70,7 @@ CURL_DEF_TOKEN $1
fi
AS_VAR_POPDEF([ac_Def])dnl
AS_VAR_POPDEF([ac_HaveDef])dnl
CPPFLAGS=$OLDCPPFLAGS
])
@ -3147,3 +3151,48 @@ use vars qw(
1;
_EOF
])
dnl CURL_CPP_P
dnl
dnl Check if $cpp -P should be used for extract define values due to gcc 5
dnl splitting up strings and defines between line outputs. gcc by default
dnl (without -P) will show TEST EINVAL TEST as
dnl
dnl # 13 "conftest.c"
dnl TEST
dnl # 13 "conftest.c" 3 4
dnl 22
dnl # 13 "conftest.c"
dnl TEST
AC_DEFUN([CURL_CPP_P], [
AC_MSG_CHECKING([if cpp -P is needed])
AC_EGREP_CPP([TEST.*TEST], [
#include <errno.h>
TEST EINVAL TEST
], [cpp=no], [cpp=yes])
AC_MSG_RESULT([$cpp])
dnl we need cpp -P so check if it works then
if test "x$cpp" = "xyes"; then
AC_MSG_CHECKING([if cpp -P works])
OLDCPPFLAGS=$CPPFLAGS
CPPFLAGS="$CPPFLAGS -P"
AC_EGREP_CPP([TEST.*TEST], [
#include <errno.h>
TEST EINVAL TEST
], [cpp_p=yes], [cpp_p=no])
AC_MSG_RESULT([$cpp_p])
if test "x$cpp_p" = "xno"; then
AC_MSG_WARN([failed to figure out cpp -P alternative])
# without -P
CPPPFLAGS=$OLDCPPFLAGS
else
# with -P
CPPPFLAGS=$CPPFLAGS
fi
dnl restore CPPFLAGS
CPPFLAGS=$OLDCPPFLAGS
fi
])