add patch step for SNAP on musl

- cmake/GetSNAP.cmake: run patch or git apply to add fixes to glib-core when
	compiling with musl (i.e. POSIX).
- check wordsize with `sizeof(void*)` (from cmake) and inject into SNAP with
	the patch step
- add BUILD_BYPRODUCT so that ninja works.
- add directories to ensure include/link commands don't error
- cmake/snap-glib-base.patch: add fix for the word size.
- add fix for how they do environ
- fix single quotes in write function

Signed-off-by: Aiden Woodruff <woodra@rpi.edu>

2 files changed, 56 insertions, 1 deletions

diff --git a/cmake/GetSNAP.cmake b/cmake/GetSNAP.cmake
index 52c7b2d..ff0c968 100644
--- a/cmake/GetSNAP.cmake
+++ b/cmake/GetSNAP.cmake
@@ -1,5 +1,19 @@
 find_package(OpenMP REQUIRED)
 
+find_program(PATCH patch)
+if(PATCH)
+        set(SNAP_PATCHCMD ${PATCH} -p1 < "${CMAKE_SOURCE_DIR}/cmake/snap-glib-base.patch")
+else()
+        find_program(GIT git REQUIRED)
+        set(SNAP_PATCHCMD ${GIT} patch apply < "${CMAKE_SOURCE_DIR}/cmake/snap-glib-base.patch")
+endif()
+
+if(CMAKE_SIZEOF_VOID_P EQUAL 4)
+        set(SNAP_ARCH_FLAG -DGLib_32Bit)
+elseif(CMAKE_SIZEOF_VOID_P EQUAL 8)
+        set(SNAP_ARCH_FLAG -DGLib_64Bit)
+endif()
+
 include(ExternalProject)
 ExternalProject_Add(
         SNAP
@@ -7,16 +21,23 @@ ExternalProject_Add(
         DOWNLOAD_NO_PROGRESS TRUE
         URL https://snap.stanford.edu/releases/Snap-6.0.zip
         URL_MD5 e32a1dbea584ba4f287c616627a71ac5
+        PATCH_COMMAND ${SNAP_PATCHCMD}
         CONFIGURE_COMMAND ""
         BUILD_IN_SOURCE TRUE
-        BUILD_COMMAND make
+        BUILD_COMMAND make CXXFLAGS=${SNAP_ARCH_FLAG}
         COMMAND make -C snap-core lib
+        BUILD_BYPRODUCTS snap-core/libsnap.a
         INSTALL_COMMAND ""
         LOG_BUILD TRUE
 )
 ExternalProject_Get_Property(SNAP SOURCE_DIR)
 set(SNAP_SOURCE_DIR "${SOURCE_DIR}")
 add_library(SNAP::SNAP STATIC IMPORTED)
+# Hacky solution to ensure IMPORTED_LOCATION does not error
+file(MAKE_DIRECTORY
+        "${SNAP_SOURCE_DIR}/snap-core"
+        "${SNAP_SOURCE_DIR}/glib-core"
+)
 set_property(TARGET SNAP::SNAP
         PROPERTY IMPORTED_LOCATION
         "${SNAP_SOURCE_DIR}/snap-core/libsnap.a"
diff --git a/cmake/snap-glib-base.patch b/cmake/snap-glib-base.patch
new file mode 100644
index 0000000..42fcb41
--- /dev/null
+++ b/cmake/snap-glib-base.patch
@@ -0,0 +1,34 @@
+--- a/glib-core/base.h
++++ b/glib-core/base.h
+@@ -89,7 +89,7 @@
+   #define GLib_32Bit

+ #elif __WORDSIZE == 64 || defined(GLib_WIN64) || defined(__CYGWIN64__)

+   #define GLib_64Bit

+-#else

++#elif !defined(GLib_32Bit) && !defined(GLib_64Bit)

+   #error "Undefined word size"

+ #endif

+ 

+@@ -98,10 +98,8 @@
+     #if defined(GLib_MACOSX)

+      #include <crt_externs.h>

+      #define _environ (*_NSGetEnviron())

+-    #elif !defined(GLib_CYGWIN)

+-     #define _environ __environ

+-     extern int _daylight;

+     #else

++     extern char **environ;

+      #define _environ environ

+     #endif

+   #endif

+--- a/glib-core/fl.cpp
++++ a/glib-core/fl.cpp
+@@ -1210,7 +1210,7 @@
+ 

+        filesize = lseek(input, 0, SEEK_END);

+        lseek(output, filesize - 1, SEEK_SET);

+-       write(output, '\0', 1);

++       write(output, "\0", 1);

+ 

+        if((source = mmap(0, filesize, PROT_READ, MAP_SHARED, input, 0)) == (void *) -1) {

+                close(input);