From a29bd89353a05454e2545d52124f9a1a61b4e3e3 Mon Sep 17 00:00:00 2001 From: "A. Wilcox" <AWilcox@Wilcox-Tech.com> Date: Sat, 23 Jun 2018 17:57:48 -0500 Subject: [PATCH] Don't use __extension__ in C++ code A few important notes: * __extension__ is a GNU C "alternate" keyword, not a C++ keyword.[1] * __extension__ is designed to work on "expressions"; it does work on #include_next in C mode, but it has no effect in C++ mode; the warning will still appear, if enabled, even with __extension__ preceding #include_next. This is because #include_next is not considered an expression in C++, so the compiler attaches __extension__ to the first expression of the header. All of this leads us to a build failure while building at least all Mozilla software. Moz has an alternate -isystem dir searched before /usr/include that overrides some headers, including <features.h>. The first statement in each of these headers is a #pragma, and since __extension__ is looking for an expression, and #pragma is a "null" expression, we end up with the following error: dist/system_wrappers/features.h:1:9: error: '#pragma' is not allowed here Since __extension__ has no effect on #include_next in C++ mode anyway, and since it can cause breakage, this commit omits __extension__ in C++ mode. [1]: https://gcc.gnu.org/onlinedocs/gcc-6.4.0/gcc/Alternate-Keywords.html --- include/poll.h | 2 ++ include/stdio.h | 2 ++ include/stdlib.h | 4 ++++ include/string.h | 2 ++ include/sys/select.h | 2 ++ include/sys/socket.h | 2 ++ include/unistd.h | 2 ++ include/wchar.h | 8 ++++++++ 8 files changed, 24 insertions(+) diff --git a/include/poll.h b/include/poll.h index 7b42866..24691f1 100644 --- a/include/poll.h +++ b/include/poll.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_POLL_H #define _FORTIFY_POLL_H +#ifndef __cplusplus __extension__ +#endif #include_next <poll.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/stdio.h b/include/stdio.h index b67f9ce..a965184 100644 --- a/include/stdio.h +++ b/include/stdio.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_STDIO_H #define _FORTIFY_STDIO_H +#ifndef __cplusplus __extension__ +#endif #include_next <stdio.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/stdlib.h b/include/stdlib.h index 7ff5746..ef70995 100644 --- a/include/stdlib.h +++ b/include/stdlib.h @@ -16,12 +16,16 @@ #ifndef _FORTIFY_STDLIB_H #define _FORTIFY_STDLIB_H +#ifndef __cplusplus __extension__ +#endif #include_next <stdlib.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 #if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) || defined(_BSD_SOURCE) +#ifndef __cplusplus __extension__ +#endif #include_next <limits.h> #endif diff --git a/include/string.h b/include/string.h index ff237b0..43c7485 100644 --- a/include/string.h +++ b/include/string.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_STRING_H #define _FORTIFY_STRING_H +#ifndef __cplusplus __extension__ +#endif #include_next <string.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/sys/select.h b/include/sys/select.h index e4e398f..bcee8be 100644 --- a/include/sys/select.h +++ b/include/sys/select.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_SYS_SELECT_H #define _FORTIFY_SYS_SELECT_H +#ifndef __cplusplus __extension__ +#endif #include_next <sys/select.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/sys/socket.h b/include/sys/socket.h index 7d3f023..ad6ab2d 100644 --- a/include/sys/socket.h +++ b/include/sys/socket.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_SYS_SOCKET_H #define _FORTIFY_SYS_SOCKET_H +#ifndef __cplusplus __extension__ +#endif #include_next <sys/socket.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/unistd.h b/include/unistd.h index d3ab246..71dda84 100644 --- a/include/unistd.h +++ b/include/unistd.h @@ -16,7 +16,9 @@ #ifndef _FORTIFY_UNISTD_H #define _FORTIFY_UNISTD_H +#ifndef __cplusplus __extension__ +#endif #include_next <unistd.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 diff --git a/include/wchar.h b/include/wchar.h index 7394598..3cb6f92 100644 --- a/include/wchar.h +++ b/include/wchar.h @@ -16,13 +16,21 @@ #ifndef _FORTIFY_WCHAR_H #define _FORTIFY_WCHAR_H +#ifndef __cplusplus __extension__ +#endif #include_next <limits.h> +#ifndef __cplusplus __extension__ +#endif #include_next <stdlib.h> +#ifndef __cplusplus __extension__ +#endif #include_next <string.h> +#ifndef __cplusplus __extension__ +#endif #include_next <wchar.h> #if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0 -- 2.15.0