BaseTools: Fix build on FreeBSD and allow use of non-gcc system compiler

On FreeBSD, uuid.h is in /usr/include, not /usr/include/uuid.

Fix some errors when building using clang caused by self-assignment: the
preferred way to 'use' a variable is '(void)x;', not 'x = x;'.

Where the system provides $(CC) etc. by default, don't override it to be gcc.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Bruce Cran <bruce@cran.org.uk>
Reviewed-by: Yingke Liu <yingke.d.liu@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17866 6f19259b-4bc3-4df7-8a09-765794883524

BaseTools/Source/C/GenFv/GenFvInternalLib.c

@@ -16,8 +16,13 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 //
 // Include files
 //
-#ifdef __GNUC__
+
+#if defined(__FreeBSD__)
+#include <uuid.h>
+#elif defined(__GNUC__)
 #include <uuid/uuid.h>
+#endif
+#ifdef __GNUC__
 #include <sys/stat.h>
 #endif
 #include <string.h>

BaseTools/Source/C/LzmaCompress/LzmaCompress.c

@@ -43,8 +43,8 @@ const char *kCantWriteMessage = "Can not write output file";
 const char *kCantAllocateMessage = "Can not allocate memory";
 const char *kDataErrorMessage = "Data error";
 
-static void *SzAlloc(void *p, size_t size) { p = p; return MyAlloc(size); }
-static void SzFree(void *p, void *address) { p = p; MyFree(address); }
+static void *SzAlloc(void *p, size_t size) { (void)p; return MyAlloc(size); }
+static void SzFree(void *p, void *address) { (void)p; MyFree(address); }
 static ISzAlloc g_Alloc = { SzAlloc, SzFree };
 
 static Bool mQuietMode = False;

BaseTools/Source/C/LzmaCompress/Sdk/C/LzmaEnc.c

@@ -2112,7 +2112,7 @@ void LzmaEnc_Finish(CLzmaEncHandle pp)
   if (p->mtMode)
     MatchFinderMt_ReleaseStream(&p->matchFinderMt);
   #else
-  pp = pp;
+  (void)pp;
   #endif
 }
 

BaseTools/Source/C/Makefiles/header.makefile

@@ -21,11 +21,11 @@ CYGWIN:=$(findstring CYGWIN, $(shell uname -s))
 LINUX:=$(findstring Linux, $(shell uname -s))
 DARWIN:=$(findstring Darwin, $(shell uname -s))
 
-CC = gcc
-CXX = g++
-AS = gcc
-AR = ar
-LD = ld
+CC ?= gcc
+CXX ?= g++
+AS ?= gcc
+AR ?= ar
+LD ?= ld
 LINKER ?= $(CC)
 ifeq ($(ARCH), IA32)
 ARCH_INCLUDE = -I $(MAKEROOT)/Include/Ia32/

BaseTools/Source/C/VfrCompile/Pccts/antlr/makefile

@@ -164,7 +164,7 @@ PCCTS_H=../h
 #
 #   UNIX  (default)
 #
-CC=gcc
+CC?=gcc
 COPT=-O
 ANTLR=${BIN_DIR}/antlr
 DLG=${BIN_DIR}/dlg