[MacPorts] #71162: xar @1.8.0.501_0: error: implicit declaration of function 'xar_prop_get_expect_notnull' is invalid in C99 [-Werror, -Wimplicit-function-declaration]

[MacPorts]

#71162: xar @1.8.0.501_0: error: implicit declaration of function
'xar_prop_get_expect_notnull' is invalid in C99 [-Werror,-Wimplicit-
function-declaration]
-------------------------+------------------------------
  Reporter:  ryandesign  |      Owner:  Schamschula
      Type:  defect      |     Status:  assigned
  Priority:  High        |  Milestone:
 Component:  ports       |    Version:  2.10.2
Resolution:              |   Keywords:  bigsur, monterey
      Port:  xar         |
-------------------------+------------------------------
Changes (by ryandesign):

 * keywords:  monterey => bigsur, monterey


Comment:

 Replying to [ticket:71162 ryandesign]:
 > {{{
 > src/xar.c:678:11: error: implicit declaration of function
 'xar_prop_get_expect_notnull' is invalid in C99 [-Werror,-Wimplicit-
 function-declaration]
 >         if( 0 != xar_prop_get_expect_notnull((xar_file_t)x,
 "checksum/offset" ,&value) ) {
 >                  ^
 > }}}

 `xar_prop_get_expect_notnull` is declared in xar.h and defined in xar.c.
 xar.c does `#include "xar.h"` thanks to patch-stdout.diff. Seems like that
 should be enough.

 However, I see that
 /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/xar/xar.h
 also exists and it does not declare `xar_prop_get_expect_notnull`. It
 seems to be including this file instead of the one included with the xar
 source. I'm not sure why. The command looks right to me:

 {{{
 /usr/bin/clang -pipe -Os
 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk -arch
 x86_64  -Iinclude -Iinclude -I/opt/local/include
 -isysroot/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk
 -I/opt/local/include/libxml2 -c src/xar.c -o src/xar.o
 }}}

 I thought `-I` paths would be looked in first, before `-isysroot` and
 `-isystem` paths. But the log shows it is accessing the file from the SDK:

 {{{
 src/xar.c:186:6: warning: 'xar_open' is deprecated: first deprecated in
 macOS 12.0 - xar is a deprecated file format and should not be used.
 [-Wdeprecated-declarations]
         x = xar_open(filename, WRITE);
             ^
 /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/xar/xar.h:158:7:
 note: 'xar_open' has been explicitly marked deprecated here
 }}}

 Different OS versions including different versions of xar.h would
 certainly account for why this problem occurs on some OS versions and not
 others, but I don't think we want to use the OS version of xar.h on any OS
 version.

 I see that xar.c does also `#include "xar_internal.h"`, before including
 xar.h. xar_internal.h does this:

 {{{#!c
 #ifdef XARSIG_BUILDING_WITH_XAR
 #include "xar.h"
 #else
 #include <xar/xar.h>
 #endif // XARSIG_BUILDING_WITH_XAR
 }}}

 So if `XARSIG_BUILDING_WITH_XAR` is defined then we wouldn't need to patch
 xar.c to include xar.h. And if `XARSIG_BUILDING_WITH_XAR` is not defined
 then the include of `<xar/xar.h>` will certainly find the system version,
 not the one in the xar source.

 xar.xcodeproj/project.pbxproj defines `XARSIG_BUILDING_WITH_XAR`:

 {{{
                                 OTHER_CFLAGS =
 "-DXARSIG_BUILDING_WITH_XAR";
 }}}

 Maybe all we need to do is define that in the portfile as well, since the
 portfile doesn't build using the Xcode project. I can try it in a moment.

-- 
Ticket URL: <https://trac.macports.org/ticket/71162#comment:4>
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