Misc CMAKE build fixes (SynoCommunity#5658)

* native-cmake.mk: Allow changing default build dir

* tc.mk: Use abspath to remove all '//' use-cases from tc_vars.*

* cross-cmake.mk: Set nasm only for x86 and set PKG_CONFIG_LIBDIR

* cross-cmake.mk: Various fixes and enhancements

1. Use abspath instead of realpath as it does not check if
   location does exists.  Usage of realpath sets variables to
   empty '' in some cases as the build may not have started yet.
   Usage of abspath solves that issue entirely
2. Allow NOT to build shared libraries by default.  Building LLVM
   requires this to be unset or set to OFF so shared libraries
   are disabled by default
3. Enforce setting x86asm using CMAKE_USE_NASM only to i686 & x86_64

mk/spksrc.cross-cmake-env.mk

@@ -33,7 +33,11 @@ CMAKE_FIND_ROOT_PATH_MODE_INCLUDE = ONLY
 CMAKE_INSTALL_RPATH = $(INSTALL_PREFIX)/lib
 CMAKE_INSTALL_RPATH_USE_LINK_PATH = TRUE
 CMAKE_BUILD_WITH_INSTALL_RPATH = TRUE
+
+# Allow building shared libraries to be manually set
+ifeq ($(filter -DBUILD_SHARED_LIBS%,$(CMAKE_ARGS)),)
 BUILD_SHARED_LIBS = ON
+endif
 
 # Configuration for CMake build
 CMAKE_TOOLCHAIN_NAME = $(ARCH)-toolchain.cmake
@@ -65,15 +69,15 @@ endif
 # Use native cmake (latest stable)
 ifeq ($(strip $(USE_NATIVE_CMAKE)),1)
   BUILD_DEPENDS += native/cmake
-  CMAKE_PATH = $(realpath $(WORK_DIR)/../../../native/cmake/work-native/install/usr/local/bin)
+  CMAKE_PATH = $(abspath $(PWD)/../../native/cmake/work-native/install/usr/local/bin)
   ENV += PATH=$(CMAKE_PATH):$$PATH
   export PATH := $(CMAKE_PATH):$(PATH)
 endif
 
 # Use native cmake (Debian 10 "Buster")
 ifeq ($(strip $(USE_NATIVE_CMAKE_LEGACY)),1)
   BUILD_DEPENDS += native/cmake-legacy
-  CMAKE_PATH = $(realpath $(WORK_DIR)/../../../native/cmake-legacy/work-native/install/usr/local/bin)
+  CMAKE_PATH = $(abspath $(PWD)/../../native/cmake-legacy/work-native/install/usr/local/bin)
   ENV += PATH=$(CMAKE_PATH):$$PATH
   export PATH := $(CMAKE_PATH):$(PATH)
 endif
@@ -86,17 +90,25 @@ ifeq ($(strip $(CMAKE_USE_NINJA)),1)
   CMAKE_ARGS += -G Ninja
 endif
 
-# Set default ASM build environment
+# Set default X86ASM build environment
 # At toolchain step variables are not yet evaluated
 # resulting in inability to set in toolchain file
+#
+# ARM architecture may expect to be assembled with a C compiler as frontend:
+#    .s is raw assembly passed to as
+#    .S is assembly which expects to be preprocessed by a cpp then fed to assembler
+# Setting the following for ARM may help:
+#    ENV += AS=$(abspath $(PWD)/../../toolchain/syno-$(ARCH)-$(TCVERSION)/work/$(TC_TARGET)/bin/$(TC_PREFIX)gcc)
 ifeq ($(strip $(CMAKE_USE_NASM)),1)
+  # Define x86asm
+  ifeq ($(findstring $(ARCH),$(i686_ARCHS) $(x64_ARCHS)),$(ARCH))
   DEPENDS += native/nasm
-  NASM_PATH = $(realpath $(WORK_DIR)/../../../native/nasm/work-native/install/usr/local/bin)
+  NASM_PATH = $(abspath $(PWD)/../../native/nasm/work-native/install/usr/local/bin)
   ENV += PATH=$(NASM_PATH):$$PATH
   ENV += AS=$(NASM_PATH)/nasm
-  export PATH := $(NASM_PATH):$(PATH)
   ENABLE_ASSEMBLY = ON
   CMAKE_ASM_COMPILER = $(NASM_PATH)/nasm
+  endif
 else
   CMAKE_USE_NASM = 0
 endif

mk/spksrc.cross-cmake.mk

@@ -45,10 +45,12 @@ cmake_pkg_toolchain:
 	@cat $(CMAKE_TOOLCHAIN_WRK) ; \
 	echo
 ifeq ($(strip $(CMAKE_USE_NASM)),1)
+ifeq ($(findstring $(ARCH),$(i686_ARCHS) $(x64_ARCHS)),$(ARCH))
 	@echo "# set assembly compiler" ; \
 	echo "set(ENABLE_ASSEMBLY $(ENABLE_ASSEMBLY))" ; \
 	echo "set(CMAKE_ASM_COMPILER $(CMAKE_ASM_COMPILER))" ; \
 	echo
+endif
 endif
 	@echo "# set compiler flags for cross-compiling" ; \
 	echo 'set(CMAKE_C_FLAGS "$(CFLAGS) $(CMAKE_C_FLAGS) $(ADDITIONAL_CFLAGS)")' ; \
@@ -57,11 +59,18 @@ endif
 	echo 'set(CMAKE_EXE_LINKER_FLAGS "$(LDFLAGS) $(CMAKE_EXE_LINKER_FLAGS) $(ADDITIONAL_LDFLAGS)")' ; \
 	echo 'set(CMAKE_SHARED_LINKER_FLAGS "$(LDFLAGS) $(CMAKE_SHARED_LINKER_FLAGS) $(ADDITIONAL_LDFLAGS)")' ; \
 	echo
+ifneq ($(strip $(BUILD_SHARED_LIBS)),)
+	@echo "# build shared library" ; \
+	echo "set(BUILD_SHARED_LIBS $(BUILD_SHARED_LIBS))"
+endif
 	@echo "# define library rpath" ; \
 	echo "set(CMAKE_INSTALL_RPATH $(subst $() $(),:,$(CMAKE_INSTALL_RPATH)))" ; \
 	echo "set(CMAKE_INSTALL_RPATH_USE_LINK_PATH $(CMAKE_INSTALL_RPATH_USE_LINK_PATH))" ; \
 	echo "set(CMAKE_BUILD_WITH_INSTALL_RPATH $(CMAKE_BUILD_WITH_INSTALL_RPATH))" ; \
 	echo
+	@echo "# set pkg-config path" ; \
+	echo 'set(ENV{PKG_CONFIG_LIBDIR} "$(abspath $(PKG_CONFIG_LIBDIR))")' ; \
+	echo 'set(ENV{PKG_CONFIG_SYSROOT_DIR} "$(abspath $(INSTALL_DIR))")'
 
 .PHONY: cmake_configure_target
 

mk/spksrc.native-cmake.mk

@@ -35,6 +35,11 @@ ifeq ($(strip $(CONFIGURE_TARGET)),)
 CONFIGURE_TARGET = cmake_configure_target
 endif
 
+# install
+ifeq ($(strip $(CMAKE_DIR)),)
+CMAKE_DIR = $(WORK_DIR)/$(PKG_DIR)
+endif
+
 ifneq ($(strip $(CMAKE_USE_NINJA)),1)
 # compile
 ifeq ($(strip $(COMPILE_TARGET)),)
@@ -59,7 +64,7 @@ cmake_configure_target:
 	@$(MSG)    - Path BUILD_DIR = $(CMAKE_BUILD_DIR)
 	$(RUN) rm -rf CMakeCache.txt CMakeFiles
 	$(RUN) mkdir --parents $(CMAKE_BUILD_DIR)
-	cd $(CMAKE_BUILD_DIR) && env $(ENV) cmake $(CMAKE_ARGS) $(WORK_DIR)/$(PKG_DIR)
+	cd $(CMAKE_BUILD_DIR) && env $(ENV) cmake $(CMAKE_ARGS) $(CMAKE_DIR)
 
 .PHONY: cmake_compile_target
 

mk/spksrc.tc-flags.mk

@@ -37,23 +37,23 @@ TC_PREFIX = $(TC_TARGET)-
 endif
 
 ifeq ($(strip $(TC_INCLUDE)),)
-TC_INCLUDE = $(TC_SYSROOT)/usr/include
+TC_INCLUDE = $(abspath $(TC_SYSROOT)/usr/include)
 endif
 
 ifeq ($(strip $(TC_LIBRARY)),)
-TC_LIBRARY = $(TC_SYSROOT)/lib
+TC_LIBRARY = $(abspath $(TC_SYSROOT)/lib)
 endif
 
-CFLAGS += -I$(WORK_DIR)/$(TC_TARGET)/$(TC_INCLUDE) $(TC_EXTRA_CFLAGS)
-CFLAGS += -I$(INSTALL_DIR)/$(INSTALL_PREFIX)/include
+CFLAGS += -I$(abspath $(WORK_DIR)/$(TC_TARGET)/$(TC_INCLUDE)) $(TC_EXTRA_CFLAGS)
+CFLAGS += -I$(abspath $(INSTALL_DIR)/$(INSTALL_PREFIX)/include)
 
-CPPFLAGS += -I$(WORK_DIR)/$(TC_TARGET)/$(TC_INCLUDE) $(TC_EXTRA_CFLAGS)
-CPPFLAGS += -I$(INSTALL_DIR)/$(INSTALL_PREFIX)/include
+CPPFLAGS += -I$(abspath $(WORK_DIR)/$(TC_TARGET)/$(TC_INCLUDE)) $(TC_EXTRA_CFLAGS)
+CPPFLAGS += -I$(abspath $(INSTALL_DIR)/$(INSTALL_PREFIX)/include)
 
-CXXFLAGS += -I$(WORK_DIR)/$(TC_TARGET)/$(TC_INCLUDE) $(TC_EXTRA_CFLAGS)
-CXXFLAGS += -I$(INSTALL_DIR)/$(INSTALL_PREFIX)/include
+CXXFLAGS += -I$(abspath $(WORK_DIR)/$(TC_TARGET)/$(TC_INCLUDE)) $(TC_EXTRA_CFLAGS)
+CXXFLAGS += -I$(abspath $(INSTALL_DIR)/$(INSTALL_PREFIX)/include)
 
-LDFLAGS += -L$(WORK_DIR)/$(TC_TARGET)/$(TC_LIBRARY) $(TC_EXTRA_CFLAGS)
-LDFLAGS += -L$(INSTALL_DIR)/$(INSTALL_PREFIX)/lib
-LDFLAGS += -Wl,--rpath-link,$(INSTALL_DIR)/$(INSTALL_PREFIX)/lib
-LDFLAGS += -Wl,--rpath,$(INSTALL_PREFIX)/lib
+LDFLAGS += -L$(abspath $(WORK_DIR)/$(TC_TARGET)/$(TC_LIBRARY)) $(TC_EXTRA_CFLAGS)
+LDFLAGS += -L$(abspath $(INSTALL_DIR)/$(INSTALL_PREFIX)/lib)
+LDFLAGS += -Wl,--rpath-link,$(abspath $(INSTALL_DIR)/$(INSTALL_PREFIX)/lib)
+LDFLAGS += -Wl,--rpath,$(abspath $(INSTALL_PREFIX)/lib)

mk/spksrc.tc.mk

@@ -119,10 +119,7 @@ endif
 	echo ; \
 	echo "# search headers and libraries in the target environment" ; \
 	echo "set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY $(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY))" ; \
-	echo "set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE $(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE))" ; \
-	echo ; \
-	echo "# always build shared library" ; \
-	echo "set(BUILD_SHARED_LIBS $(BUILD_SHARED_LIBS))"
+	echo "set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE $(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE))"
 
 .PHONY: meson_vars
 meson_vars: