MacOS: Support CommandLineTools for building (#1371)

Full Xcode application which can take up-to 40GB of disk space is not
necessary for building VeraCrypt, rather the CommandLineTools for XCode
are sufficient which only take few gigabytes. Instead of hardcoding the SDK
location, use xcrun --show-sdk-path to support also the CommandLineTools
instance.

The reason for switching the logic for the XCode version is because the
xcodebuild will not report a correct XCode version for the CommandLineTools,
thus it can't be relied for whether to use the -Wl,-ld_classic flags.
Instead, we can just check the ld version in use in the active developer
directory, and see whether we are using dyld (the new) or ld64 (the old).

README.md

@@ -85,7 +85,7 @@ it is also available [online](https://www.veracrypt.fr/en/CompilingGuidelineLinu
 
 - GNU Make
 - GNU C++ Compiler 4.0 or compatible
-- Apple Xcode (Mac OS X only)
+- Apple Xcode or Xcode command line tools (Mac OS X only)
 - YASM 1.3.0 or newer (Linux only, x86/x64 architecture only)
 - pkg-config
 - wxWidgets 3.0 shared library and header files installed or

src/Makefile

@@ -294,7 +294,10 @@ ifeq "$(shell uname -s)" "Darwin"
 	#check to see if XCode 3 path exists.Otherwise, use XCode 4 path
 	VC_OSX_SDK_PATH := /Developer/SDKs/MacOSX$(VC_OSX_SDK).sdk
 	ifeq ($(wildcard $(VC_OSX_SDK_PATH)/SDKSettings.plist),)
-		VC_OSX_SDK_PATH := /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX$(VC_OSX_SDK).sdk
+		VC_OSX_SDK_PATH := $(shell xcrun --sdk macosx$(VC_OSX_SDK) --show-sdk-path)
+		ifeq ($(VC_OSX_SDK_PATH),)
+$(error Specified SDK version was not found, ensure your active developer directory is correct through xcode-select)
+		endif
 	endif
 	
 	#----- Legacy build if OSX <= 10.8: we build both 32-bit and 64-bit ----
@@ -310,17 +313,12 @@ ifeq "$(shell uname -s)" "Darwin"
 	CXXFLAGS += -std=c++11
 	C_CXX_FLAGS += -DTC_UNIX -DTC_BSD -DTC_MACOSX -mmacosx-version-min=$(VC_OSX_TARGET) -isysroot $(VC_OSX_SDK_PATH)
 	LFLAGS += -mmacosx-version-min=$(VC_OSX_TARGET) -Wl,-syslibroot $(VC_OSX_SDK_PATH)
-	#Xcode 15 linker emits a warning "no platform load command found" when linking object files generated by yasm
+	# Xcode 15 linker emits a warning "no platform load command found" when linking object files generated by yasm
 	# To suppress this warning, we need to use -Wl,-ld_classic flag in order to use the old ld64 linker
 	# https://mjtsai.com/blog/2024/03/15/xcode-15-no-platform-load-command-found/
-	# Check Xcode version for using specific linker flag
+	# We can check whether newer linker is in use if ld -v reports dyld instead of ld64.
-	XCODE_VERSION := $(shell xcodebuild -version 2>/dev/null | grep 'Xcode' | sed -E 's/Xcode ([0-9]+).*/\1/')
+	ifeq ($(shell xcrun --sdk macosx$(VC_OSX_SDK) ld -v 2>&1 | grep -oE 'PROJECT:[^-]+' | cut -d: -f2),dyld)
-	ifneq ($(XCODE_VERSION),)
+		LFLAGS += -Wl,-ld_classic
-		ifeq "$(shell expr $(XCODE_VERSION) \>= 15)" "1"
-			LFLAGS += -Wl,-ld_classic
-		endif
-	else
-		$(error Xcode not found, please check your installation)
 	endif
 
 	WX_CONFIGURE_FLAGS += --with-macosx-version-min=$(VC_OSX_TARGET) --with-macosx-sdk=$(VC_OSX_SDK_PATH)

src/Readme.txt

@@ -101,7 +101,7 @@ Requirements for Building VeraCrypt for Linux and Mac OS X:
 
 - GNU Make
 - GNU C++ Compiler 4.0 or compatible
-- Apple Xcode (Mac OS X only)
+- Apple Xcode or Xcode command line tools (Mac OS X only)
 - YASM 1.3.0 or newer (Linux only, x86/x64 architecture only)
 - pkg-config
 - wxWidgets 3.0 shared library and header files installed or