7.6.0-beta1 fails to build (error: unknown type name 'siginfo_t)

[sebastic]

The Debian package build for MapServer 7.6.0-beta1 fails to build due to an issue with PHP MapScript NG:

[ 79%] Building C object mapscript/phpng/CMakeFiles/php_mapscriptng.dir/CMakeFiles/php_mapscriptng.dir/mapscriptPHP7_wrap.c.o
cd "/build/mapserver-7.6.0~beta1/obj-x86_64-linux-gnu/mapscript/phpng" && /usr/bin/cc -DPROJ_VERSION_MAJOR=7 -Dphp_mapscriptng_EXPORTS -I"/build/mapserver-7.6.0~beta1/obj-x86_64-linux-gnu/mapscript/phpng"  -I"/build/mapserver-7.6.0~beta1
/obj-x86_64-linux-gnu" -I"/build/mapserver-7.6.0~beta1/renderers/agg/include" -I"/build/mapserver-7.6.0~beta1/mapscript/v8" -I/usr/include/freetype2 -I"/build/mapserver-7.6.0~beta1/obj-x86_64-linux-gnu/renderers/mvt" -I/usr/include/fribi
di -I/usr/include/harfbuzz -I/usr/include/cairo -I/usr/include/postgresql -I/usr/include/gdal -I/usr/include/librsvg-2.0 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/glib-2.0 -I/usr/lib/x86_64
-linux-gnu/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/uuid -I/usr/include/libpng16 -I/usr/include/libxml2 -I/usr/include/php/20190902 -I/usr/include/php/20190902/main -I/usr/include/php/20190902/TSRM -I/usr/include/php/20190
902/Zend -I/usr/include/php/20190902/ext -I/usr/include/php/20190902/ext/date/lib -I"/build/mapserver-7.6.0~beta1/mapscript/swiginc" -I"/build/mapserver-7.6.0~beta1/mapscript" -I"/build/mapserver-7.6.0~beta1/mapscript/phpng" -I"/build/ma
pserver-7.6.0~beta1/obj-x86_64-linux-gnu/mapscript/phpng"  -g -O2 -fdebug-prefix-map=/build/mapserver-7.6.0~beta1=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -Wl,-z,relro -Wl,-z,now -Wdate-
time -D_FORTIFY_SOURCE=2 -Wall -Werror=format-security -O2 -g -DNDEBUG -fPIC   -Wno-unused-label -std=c99 -o CMakeFiles/php_mapscriptng.dir/CMakeFiles/php_mapscriptng.dir/mapscriptPHP7_wrap.c.o   -c "/build/mapserver-7.6.0~beta1/obj-x86_
64-linux-gnu/mapscript/phpng/CMakeFiles/php_mapscriptng.dir/mapscriptPHP7_wrap.c"
In file included from /usr/include/php/20190902/Zend/zend.h:41,
                 from /build/mapserver-7.6.0~beta1/obj-x86_64-linux-gnu/mapscript/phpng/CMakeFiles/php_mapscriptng.dir/mapscriptPHP7_wrap.c:747:
/usr/include/php/20190902/Zend/zend_signal.h:44:2: error: unknown type name 'siginfo_t'
   44 |  siginfo_t *siginfo;
      |  ^~~~~~~~~
In file included from /usr/include/php/20190902/Zend/zend.h:41,
                 from /build/mapserver-7.6.0~beta1/obj-x86_64-linux-gnu/mapscript/phpng/CMakeFiles/php_mapscriptng.dir/mapscriptPHP7_wrap.c:747:
/usr/include/php/20190902/Zend/zend_signal.h:95:53: warning: 'struct sigaction' declared inside parameter list will not be visible outside of this definition or declaration
   95 | ZEND_API int zend_sigaction(int signo, const struct sigaction *act, struct sigaction *oldact);
      |                                                     ^~~~~~~~~
/build/mapserver-7.6.0~beta1/obj-x86_64-linux-gnu/mapscript/phpng/CMakeFiles/php_mapscriptng.dir/mapscriptPHP7_wrap.c: In function '_intarrayTo_int':
/build/mapserver-7.6.0~beta1/obj-x86_64-linux-gnu/mapscript/phpng/CMakeFiles/php_mapscriptng.dir/mapscriptPHP7_wrap.c:4214:29: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
 4214 |     return (void *)((int)  ((intarray) x));
      |                             ^
/build/mapserver-7.6.0~beta1/obj-x86_64-linux-gnu/mapscript/phpng/CMakeFiles/php_mapscriptng.dir/mapscriptPHP7_wrap.c:4214:12: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
 4214 |     return (void *)((int)  ((intarray) x));
      |            ^

Full buildlog

Note that MapServer 7.4.4 built successfully with the same PHP version (which used -D_GNU_SOURCE).

This looks suspicious:

+# Set C++ version
+# Make CMAKE_CXX_STANDARD available as cache option overridable by user
+set(CMAKE_CXX_STANDARD 11
+  CACHE STRING "C++ standard version to use (default is 11)")
+message(STATUS "Requiring C++${CMAKE_CXX_STANDARD}")
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+message(STATUS "Requiring C++${CMAKE_CXX_STANDARD} - done")
+
+# Set C99 version
+# Make CMAKE_C_STANDARD available as cache option overridable by user
+set(CMAKE_C_STANDARD 99
+  CACHE STRING "C standard version to use (default is 99)")
+message(STATUS "Requiring C${CMAKE_C_STANDARD}")
+set(CMAKE_C_STANDARD_REQUIRED ON)
+set(CMAKE_C_EXTENSIONS OFF)
+message(STATUS "Requiring C${CMAKE_C_STANDARD} - done")

-D_POSIX_C_SOURCE=199309L is required for siginfo_t, that's likely one of the disabled extensions.

Adding -D_GNU_SOURCE resolves the issue.

[jmckenna]

PR #6018 fixes issue on xenial (SWIG 4.0.1, PHP 7.2.29)