diff options
| -rw-r--r-- | doc/autoconf.texi | 19 | ||||
| -rw-r--r-- | lib/autoconf/c.m4 | 16 |
2 files changed, 23 insertions, 12 deletions
diff --git a/doc/autoconf.texi b/doc/autoconf.texi index 43df8f32..4bd6e9e7 100644 --- a/doc/autoconf.texi +++ b/doc/autoconf.texi @@ -7371,7 +7371,9 @@ For the compiler @var{compiler}, this macro caches its result in the @evindex CPP @ovindex CPP Set output variable @code{CPP} to a command that runs the -C preprocessor. If @samp{$CC -E} doesn't work, @file{/lib/cpp} is used. +C preprocessor. If @samp{$CC -E} doesn't work, tries @code{cpp} and +@file{/lib/cpp}, in that order. + It is only portable to run @code{CPP} on files with a @file{.c} extension. @@ -7742,7 +7744,10 @@ C++, the @option{-std=gnu++@var{nn}} options may be used, but not the @evindex CXXCPP @ovindex CXXCPP Set output variable @code{CXXCPP} to a command that runs the C++ -preprocessor. If @samp{$CXX -E} doesn't work, @file{/lib/cpp} is used. +preprocessor. If @samp{$CXX -E} doesn't work, tries @code{cpp} and +@file{/lib/cpp}, in that order. Because of this fallback, @code{CXXCPP} +may or may not set C++-specific predefined macros (such as @code{__cplusplus}). + It is portable to run @code{CXXCPP} only on files with a @file{.c}, @file{.C}, @file{.cc}, or @file{.cpp} extension. @@ -7799,7 +7804,10 @@ compiler (@option{-O2} on systems where the compiler does not accept @evindex OBJCPP @ovindex OBJCPP Set output variable @code{OBJCPP} to a command that runs the Objective C -preprocessor. If @samp{$OBJC -E} doesn't work, @file{/lib/cpp} is used. +preprocessor. If @samp{$OBJC -E} doesn't work, tries @code{cpp} and +@file{/lib/cpp}, in that order. Because of this fallback, @code{CXXCPP} +may or may not set Objective-C-specific predefined macros (such as +@code{__OBJC__}). @end defmac @@ -7840,7 +7848,10 @@ compiler (@option{-O2} on systems where the compiler does not accept @evindex OBJCXXCPP @ovindex OBJCXXCPP Set output variable @code{OBJCXXCPP} to a command that runs the Objective C++ -preprocessor. If @samp{$OBJCXX -E} doesn't work, @file{/lib/cpp} is used. +preprocessor. If @samp{$OBJCXX -E} doesn't work, tries @code{cpp} and +@file{/lib/cpp}, in that order. Because of this fallback, @code{CXXCPP} +may or may not set Objective-C++-specific predefined macros (such as +@code{__cplusplus} and @code{__OBJC__}). @end defmac diff --git a/lib/autoconf/c.m4 b/lib/autoconf/c.m4 index 5d6e7b71..fe6aa2b6 100644 --- a/lib/autoconf/c.m4 +++ b/lib/autoconf/c.m4 @@ -385,8 +385,8 @@ fi if test -z "$CPP"; then AC_CACHE_VAL([ac_cv_prog_CPP], [dnl - # Double quotes because CPP needs to be expanded - for CPP in "$CC -E" "$CC -E -traditional-cpp" "/lib/cpp" + # Double quotes because $CC needs to be expanded + for CPP in "$CC -E" "$CC -E -traditional-cpp" cpp /lib/cpp do _AC_PROG_PREPROC_WORKS_IFELSE([break]) done @@ -644,8 +644,8 @@ AC_MSG_CHECKING([how to run the C++ preprocessor]) if test -z "$CXXCPP"; then AC_CACHE_VAL(ac_cv_prog_CXXCPP, [dnl - # Double quotes because CXXCPP needs to be expanded - for CXXCPP in "$CXX -E" "/lib/cpp" + # Double quotes because $CXX needs to be expanded + for CXXCPP in "$CXX -E" cpp /lib/cpp do _AC_PROG_PREPROC_WORKS_IFELSE([break]) done @@ -837,8 +837,8 @@ AC_MSG_CHECKING([how to run the Objective C preprocessor]) if test -z "$OBJCPP"; then AC_CACHE_VAL(ac_cv_prog_OBJCPP, [dnl - # Double quotes because OBJCPP needs to be expanded - for OBJCPP in "$OBJC -E" "/lib/cpp" + # Double quotes because $OBJC needs to be expanded + for OBJCPP in "$OBJC -E" cpp /lib/cpp do _AC_PROG_PREPROC_WORKS_IFELSE([break]) done @@ -976,8 +976,8 @@ AC_MSG_CHECKING([how to run the Objective C++ preprocessor]) if test -z "$OBJCXXCPP"; then AC_CACHE_VAL(ac_cv_prog_OBJCXXCPP, [dnl - # Double quotes because OBJCXXCPP needs to be expanded - for OBJCXXCPP in "$OBJCXX -E" "/lib/cpp" + # Double quotes because $OBJCXX needs to be expanded + for OBJCXXCPP in "$OBJCXX -E" cpp /lib/cpp do _AC_PROG_PREPROC_WORKS_IFELSE([break]) done |