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Bug 5234

Summary: Build fails with autoconf 2.70
Product: SDL Reporter: Ross Burton <ross>
Component: buildAssignee: Sam Lantinga <slouken>
Status: RESOLVED FIXED QA Contact: Sam Lantinga <slouken>
Severity: major    
Priority: P2 CC: sezeroz
Version: 2.0.13   
Hardware: All   
OS: All   
Attachments: configure difference before and after patch from comment #2

Description Ross Burton 2020-07-16 16:35:00 UTC 
The build fails with autoconf 2.70 (beta1):

| checking for size_t... yes 
| checking for M_PI in math.h... ../SDL2-2.0.12/configure: line 13202: CPP: command not found 
| checking how to run the C preprocessor... gcc  -E 
| ../SDL2-2.0.12/configure: line 13328: ac_fn_c_try_cpp: command not found 
| ../SDL2-2.0.12/configure: line 13328: ac_fn_c_try_cpp: command not found 
| configure: error: in `/home/pokybuild/yocto-worker/qemux86-64/build/build/tmp/work/x86_64-linux/libsdl2-native/2.0.12-r0/build': 
| configure: error: C preprocessor "gcc  -E" fails sanity check 
| See `config.log' for more details 
| WARNING: exit code 1 from a shell command. 

Discussion with autoconf upstream:

---
This is a classic M4 quoting bug.  The macro should quote the third
argument to AC_CACHE_CHECK (and really, should quote all the arguments).

The problem is that diversions do not work properly during arugment
collection so AC_REQUIRE (which depends on diversions) and many other
macros will not work properly if it is expanded during argument
collection.

Quote the arguments to AC_CACHE_CHECK and the prerequisite macros will
get expanded in the correct order.

(also WTF is with that stray AC_DEFINE outside of the macro definition?)
---
Comment 1 Ross Burton 2020-09-03 14:16:46 UTC 
Ping.  Autoconf 2.70 is coming out soon and libSDL won't build.
Comment 2 Ozkan Sezer 2020-09-10 16:33:05 UTC 
The following fixes this issue for me.  OK to apply?

diff --git a/acinclude/ac_check_define.m4 b/acinclude/ac_check_define.m4
--- a/acinclude/ac_check_define.m4
+++ b/acinclude/ac_check_define.m4
@@ -1,4 +1,4 @@
-AC_DEFUN([AC_CHECK_DEFINE],[dnl
+AC_DEFUN([AC_CHECK_DEFINE],[AC_REQUIRE([AC_PROG_CPP])dnl
   AC_CACHE_CHECK(for $1 in $2, ac_cv_define_$1,
     AC_EGREP_CPP([YES_IS_DEFINED], [
 #include <$2>
Comment 3 Ross Burton 2020-09-10 18:08:06 UTC 
The correct fix is to quote the arguments.
Comment 4 Ozkan Sezer 2020-09-10 18:58:35 UTC 
(In reply to Ross Burton from comment #3)
> The correct fix is to quote the arguments.

I tried doing that (maybe incompletely or incorrectly)
it still failed.

I suggest that you give us a working patch.
Comment 5 Ozkan Sezer 2020-09-10 20:56:06 UTC 
Created attachment 4461 [details]
configure difference before and after patch from comment #2

Also see:
http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=blob;f=NEWS#l43

The issue might be related to optimizations mentioned in there.
E.g.: without the patch from comment #2, the CPP environment
variable is ignored. So I believe AC_REQUIRE([AC_PROG_CPP]) is
is needed there. (Alternatively, AC_PROG_CPP can be added to
configure.ac .)

Still waiting for your own patch to fix the issue.
Comment 6 Ozkan Sezer 2020-09-16 05:01:31 UTC 
Since no one else provided a solution, I pushed the patch
from comment #2:
https://hg.libsdl.org/SDL/rev/2c13b7ca1997

If there is a better solution, attach a proper patch here.