Enable building JNA for Darwin arm64

- Big Sur uses a shared dylib cache to lookup system libraries and frameworks. Checking existence in the file system will fail, but loading them will succeed nevertheless.
- Arm64 calling convention requires varargs to always be passed on the stack. JNA's and ffi's argument handling logic seems to handle this case correctly, but it is important that the Java definitions match their native counterparts exactly.

native/Makefile

@@ -99,8 +99,18 @@ CFLAGS=$(PCFLAGS) $(CFLAGS_EXTRA) $(COPT) $(CDEBUG) $(CDEFINES) $(CINCLUDES) \
        -DJNA_JNI_VERSION='"$(JNA_JNI_VERSION)"' -DCHECKSUM='"$(CHECKSUM)"'
 LDFLAGS=-o $@ -shared
 ifeq ($(DYNAMIC_LIBFFI),true)
+ifeq ($(OS),darwin)
+ifeq ($(DARWIN_USE_SDK_LIBFFI),true)
+CFLAGS += -I$(SDKROOT)/usr/include/ffi
+LIBS += -L$(SDKROOT)/usr/lib -lffi
+else
 CFLAGS += $(shell pkg-config --cflags libffi 2>/dev/null || echo)
 LIBS += $(shell pkg-config --libs libffi 2>/dev/null || echo -lffi)
+endif
+else
+CFLAGS += $(shell pkg-config --cflags libffi 2>/dev/null || echo)
+LIBS += $(shell pkg-config --libs libffi 2>/dev/null || echo -lffi)
+endif
 else
 # -static-libgcc avoids gcc library incompatibilities across linux systems
 LDFLAGS += -static-libgcc
@@ -373,19 +383,26 @@ endif
 
 
 ifeq ($(OS),darwin)
-XCODE_VERSION=$(shell xcodebuild -version | grep Xcode | sed 's/^Xcode \([1-9]\).*/\1/g')
+XCODE_VERSION=$(shell xcodebuild -version | grep Xcode | sed 's/^Xcode \([1-9][0-9]*\).*/\1/g')
 JAVA_INCLUDES+=-I/System/Library/Frameworks/JavaVM.framework/Headers
 DEFAULT_ARCH=$(shell arch)
 ARCH=$(shell arch)
 HOST_CONFIG=--host $(ARCH)-apple-darwin
 FFI_ENV += CC="$(CC)" CFLAGS="-arch $(ARCH) $(ISYSROOT) $(COPT) $(CDEBUG)" CPPFLAGS="$(CDEFINES)" LD="$(LD) -arch $(ARCH)"
 ALT_ARCHS=
 ifneq ($(ARCH),i386)
+ifeq ($(shell echo "int main(void) { return 0; }" | $(CC) $(LOC_CC_OPTS) -arch i386 $(CFLAGS) -x c - -o /dev/null &>/dev/null; echo $$?),0)
 ALT_ARCHS+=i386
 endif
+endif
 ifneq ($(ARCH),x86_64)
 ALT_ARCHS+=x86_64
 endif
+ifneq ($(ARCH),arm64)
+ifeq ($(shell echo "int main(void) { return 0; }" | $(CC) $(LOC_CC_OPTS) -arch arm64 $(CFLAGS) -x c - -o /dev/null &>/dev/null; echo $$?),0)
+ALT_ARCHS+=arm64
+endif
+endif
 ifneq ($(ARCH),ppc)
 ifeq ($(XCODE_VERSION),3)
 # Xcode 3 options
@@ -401,7 +418,13 @@ JNISFX=.jnilib
 ifneq ($(SDKROOT),)
 SYSLIBROOT=-Wl,-syslibroot,$(SDKROOT)
 ISYSROOT=-isysroot $(SDKROOT)
-ARCHFLAGS=-arch i386 -arch x86_64
+ARCHFLAGS=-arch x86_64
+ifeq ($(shell echo "int main(void) { return 0; }" | $(CC) $(LOC_CC_OPTS) -arch i386 $(CFLAGS) -x c - -o /dev/null &>/dev/null; echo $$?),0)
+ARCHFLAGS+=-arch i386
+endif
+ifeq ($(shell echo "int main(void) { return 0; }" | $(CC) $(LOC_CC_OPTS) -arch arm64 $(CFLAGS) -x c - -o /dev/null &>/dev/null; echo $$?),0)
+ARCHFLAGS+=-arch arm64
+endif
 ifeq ($(XCODE_VERSION),3)
 ARCHFLAGS+=-arch ppc
 endif
@@ -410,16 +433,18 @@ endif
 PCFLAGS+=$(ISYSROOT) -x objective-c
 # JAWT no longer supported on OSX
 CDEFINES+=-DTARGET_RT_MAC_CFM=0 -DFFI_MMAP_EXEC_WRIT -DNO_JAWT
-LDFLAGS=$(ARCHFLAGS) -dynamiclib -o $@ -framework JavaVM \
+LDFLAGS=$(ARCHFLAGS) -dynamiclib -o $@ \
   -compatibility_version $(shell echo ${JNA_JNI_VERSION}|sed 's/^\([0-9][0-9]*\).*/\1/g') \
   -current_version $(JNA_JNI_VERSION) \
   -mmacosx-version-min=10.3 \
   -framework Foundation \
   $(NO_COMPACT_UNWIND) \
   -install_name ${@F} \
   $(SYSLIBROOT)
+ifeq ($(shell test $(XCODE_VERSION) -lt 12; echo $$?),0)
 # JAWT linkage handled by -framework JavaVM
-LIBS=
+LIBS+=-framework JavaVM
+endif
 endif
 
 # Unfortunately, we have to use different libffi include files depending on

test/com/sun/jna/LibraryLoadTest.java

@@ -203,13 +203,12 @@ public void testLoadLibraryWithLongName() throws Exception {
     public void testLoadFrameworkLibrary() {
         if (Platform.isMac()) {
             final String PATH = "/System/Library/Frameworks/CoreServices.framework";
-            assertTrue("CoreServices not present on this setup, expected at " + PATH, new File(PATH).exists());
             try {
                 NativeLibrary lib = NativeLibrary.getInstance("CoreServices");
                 assertNotNull("CoreServices not found", lib);
             }
             catch(UnsatisfiedLinkError e) {
-                fail("Should search /System/Library/Frameworks");
+                failCoreServices("Should search /System/Library/Frameworks: ", e, PATH);
             }
         }
     }
@@ -218,31 +217,36 @@ public void testLoadFrameworkLibraryAbsolute() {
         if (Platform.isMac()) {
             final String PATH = "/System/Library/Frameworks/CoreServices";
             final String FRAMEWORK = PATH + ".framework";
-            assertTrue("CoreServices not present on this setup, expected at " + FRAMEWORK, new File(FRAMEWORK).exists());
             try {
                 NativeLibrary lib = NativeLibrary.getInstance(PATH);
                 assertNotNull("CoreServices not found", lib);
             }
             catch(UnsatisfiedLinkError e) {
-                fail("Should try FRAMEWORK.framework/FRAMEWORK if the absolute framework (truncated) path given exists: " + e);
+                failCoreServices("Should try FRAMEWORK.framework/FRAMEWORK if the absolute framework (truncated) path given exists: ", e, FRAMEWORK);
             }
         }
     }
 
     public void testLoadFrameworkLibraryAbsoluteFull() {
         if (Platform.isMac()) {
             final String PATH = "/System/Library/Frameworks/CoreServices.framework/CoreServices";
-            assertTrue("CoreServices not present on this setup, expected at " + PATH, new File(PATH).exists());
             try {
                 NativeLibrary lib = NativeLibrary.getInstance(PATH);
                 assertNotNull("CoreServices not found", lib);
             }
             catch(UnsatisfiedLinkError e) {
-                fail("Should try FRAMEWORK verbatim if the absolute path given exists: " + e);
+                failCoreServices("Should try FRAMEWORK verbatim if the absolute path given exists: ", e, PATH);
             }
         }
     }
 
+    private void failCoreServices(String message, UnsatisfiedLinkError e, String expectedPath) {
+        if (!new File(expectedPath).exists()) {
+            message = "CoreServices not present on this setup, expected at " + expectedPath + "\n" + message;
+        }
+        fail(message + e);
+    }
+
     public void testHandleObjectMethods() {
         CLibrary lib = (CLibrary)load();
         String method = "toString";

test/com/sun/jna/VarArgsTest.java

@@ -42,8 +42,8 @@ protected List<String> getFieldOrder() {
         }
         public int addVarArgs(String fmt, Number... args);
         public String returnStringVarArgs(String fmt, Object... args);
-        public void modifyStructureVarArgs(String fmt, Object arg1, Object... args);
-        public String returnStringVarArgs2(String... args);
+        public void modifyStructureVarArgs(String fmt, Object... args);
+        public String returnStringVarArgs2(String fmt, String... args);
     }
     TestLibrary lib;
     @Override