Fix libpng and libfreetype port with wasm exceptions are enabled

For libpng we simply avoid the use of setjmp/longjmp completely.

For libfreetype the use of setjmp/longjmp is not optional so we build a
variant of the library that uses wasm exceptions for setjmp/longjmp
support.

Fixes: #19001

test/test_other.py

@@ -92,6 +92,20 @@ def metafunc(self, wasmfs):
   return metafunc
 
 
+def also_with_wasm_longjmp(f):
+  def metafunc(self, enabled):
+    if enabled:
+      self.require_wasm_eh()
+      self.emcc_args.append('-sSUPPORT_LONGJMP=wasm')
+      f(self)
+    else:
+      f(self)
+
+  metafunc._parameterize = {'': (False,),
+                            'wasm_longjmp': (True,)}
+  return metafunc
+
+
 def wasmfs_all_backends(f):
   def metafunc(self, backend):
     self.set_setting('WASMFS')
@@ -2205,6 +2219,7 @@ def test_bzip2(self):
     self.do_runf(test_file('bzip2_test.c'), 'usage: unzcrash filename',
                  emcc_args=['-sUSE_BZIP2', '-Wno-pointer-sign'])
 
+  @also_with_wasm_longjmp
   def test_freetype(self):
     # copy the Liberation Sans Bold truetype file located in the
     # <emscripten_root>/test/freetype to the compilation folder

tools/ports/freetype.py

@@ -8,11 +8,20 @@
 TAG = 'version_1'
 HASH = '0d0b1280ba0501ad0a23cf1daa1f86821c722218b59432734d3087a89acd22aabd5c3e5e1269700dcd41e87073046e906060f167c032eb91a3ac8c5808a02783'
 
+variants = {'freetype-wasm-longjmp': {'SUPPORT_LONGJMP': 'wasm'}}
+
 
 def needed(settings):
   return settings.USE_FREETYPE
 
 
+def get_lib_name(settings):
+  if settings.SUPPORT_LONGJMP == 'wasm':
+    return 'libfreetype-wasm-sjlj.a'
+  else:
+    return 'libfreetype.a'
+
+
 def get(ports, settings, shared):
   ports.fetch_project('freetype', f'https://github.com/emscripten-ports/FreeType/archive/{TAG}.zip', sha512hash=HASH)
 
@@ -90,13 +99,16 @@ def create(final):
       '-pthread'
     ]
 
+    if settings.SUPPORT_LONGJMP == 'wasm':
+      flags.append('-sSUPPORT_LONGJMP=wasm')
+
     ports.build_port(source_path, final, 'freetype', flags=flags, srcs=srcs)
 
-  return [shared.cache.get_lib('libfreetype.a', create, what='port')]
+  return [shared.cache.get_lib(get_lib_name(settings), create, what='port')]
 
 
 def clear(ports, settings, shared):
-  shared.cache.erase_lib('libfreetype.a')
+  shared.cache.erase_lib(get_lib_name(settings))
 
 
 def process_args(ports):

tools/ports/libpng.py

@@ -10,15 +10,15 @@
 HASH = '2ce2b855af307ca92a6e053f521f5d262c36eb836b4810cb53c809aa3ea2dcc08f834aee0ffd66137768a54397e28e92804534a74abb6fc9f6f3127f14c9c338'
 
 deps = ['zlib']
-variants = {'libpng-mt': {'PTHREADS': 1}}
+variants = {'libpng-wasm-sjlj': {'SUPPORT_LONGJMP': 'wasm'}}
 
 
 def needed(settings):
   return settings.USE_LIBPNG
 
 
 def get_lib_name(settings):
-  return 'libpng' + ('-mt' if settings.PTHREADS else '') + '.a'
+  return 'libpng' + ('-wasm-sjlj' if settings.SUPPORT_LONGJMP else '') + '.a'
 
 
 def get(ports, settings, shared):