Enable optional GCC install and GCC improvements

-By adding MKGCC=yes and MKGCCCMDS=yes on the make commandline
   it is now possible to compile and install GCC on the system.

   Before doing this, if you are not using the build.sh script,
   you will need to call the fetch scripts in order to retrieve
   the sources of GCC and its dependencies.

 -Reduce difference with NetBSD share/mk

   Move Minix-specific parameters from bsd.gcc.mk to bsd.own.mk,
   which is anyway patched, so that bsd.gcc.mk is now aligned
   on the NetBSD version.

 -Clean libraries dependencies, compiles stdc++ only if gcc is
   also compiled (it is part of the gcc sources)

 -Correct minix.h header sequence, cleanup spec headers.

 -Fix cross-compilation from a 32bit host targeting MINIX/arm

Change-Id: I1b234af18eed4ab5675188244e931b2a2b7bd943

lib/Makefile

@@ -97,7 +97,10 @@ SUBDIR+=	../external/public-domain/xz/lib
 #SUBDIR+=	../external/gpl3/gcc/lib/libobjc
 #SUBDIR+=	../external/gpl3/gcc/lib/libgomp
 . endif
-. if ${HAVE_GCC} >= 45 && !defined(MLIBDIR) && !defined(__MINIX)
+# LSC: Replaced __MINIX test with MKGCCCMDS, as we do not want gcc by default
+#      nor the libraries, but we still want toretain the possibility of 
+#      installing GCC from the base system.
+. if ${HAVE_GCC} >= 45 && !defined(MLIBDIR) && ${MKGCCCMDS} == "yes"
 # Should probably move GMP, MPFR and MPC builds into the GCC >= 4.5
 # specific build area, but we get better parallelism this way.
 SUBDIR+=	../external/lgpl3/gmp/lib/libgmp
@@ -152,6 +155,7 @@ SUBDIR+=	../external/gpl3/binutils/lib	# libbfd depends on libz
 .endif
 
 .if (${MKGCC} != "no" && ${MKCXX} != "no")
+.if (defined(__MINIX) && ${MKGCCCMDS} == "yes")
 . if ${HAVE_GCC} == 4
 SUBDIR+=	../gnu/lib/libstdc++-v3_4	# depends on libm
 SUBDIR+=	../gnu/lib/libsupc++4
@@ -159,6 +163,7 @@ SUBDIR+=	../gnu/lib/libsupc++4
 #SUBDIR+=	../external/gpl3/gcc/lib/libstdc++-v3
 #SUBDIR+=	../external/gpl3/gcc/lib/libsupc++
 . endif
+.endif # (defined(__MINIX) && ${MKGCCCMDS} == "yes")
 .endif
 
 #==================== 2nd library dependency barrier ====================

lib/csu/arch/earm/crt0.S

@@ -37,14 +37,15 @@ STRONG_ALIAS(_start,__start)
 
 _ENTRY(__start)
 #ifdef __minix
-        mov     r5, r2          /* cleanup */
-        mov     r4, r1          /* obj_main */
-        mov     r3, r0          /* ps_strings */
-        /* Get argc, argv, and envp from stack */
-        ldr     r0, [sp, #0x0000]
-        add     r1, sp, #0x0004
-        add     r2, r1, r0, lsl #2
-        add     r2, r2, #0x0004
+	mov	r3, r2		/* cleanup */
+	mov	r4, r1		/* obj_main */
+	and	r5, r5, #0	/* ps_strings, always NULL on MINIX */
+
+	/* Get argc, argv, and envp from stack */
+	ldr	r0, [sp, #0]	/* get argc */
+	add	r1, sp, #4	/* argv = sp + 4 */
+	add	r2, r1, r0, lsl #2	/* envp = argv + argc*4 */
+	add	r2, r2, #4	/* skip NULL terminator */
 #else
 	/*
 	 * We need to swap ps_strings and cleanup
@@ -57,10 +58,10 @@ _ENTRY(__start)
 	bic	sp, sp, #7
 
 #ifdef __minix
-	/* Store argc and argv on the stack */
-        sub     sp, sp, #8
-        str     r5, [sp, #4]
-        str     r4, [sp, #0]
+	/* Store obj and ps_strings on the stack */
+	sub	sp, sp, #8
+	str	r5, [sp, #4]
+	str	r4, [sp, #0]
 #endif
 	/*
 	 * void ___start(void (*cleanup)(void),

lib/csu/common/crt0-common.c

@@ -143,6 +143,8 @@ ___start(void (*cleanup)(void),			/* from shared loader */
 	struct ps_strings minix_ps_strings;
 
 	if (ps_strings == NULL) {
+		memset(&minix_ps_strings, 0, sizeof(minix_ps_strings));
+
 		minix_ps_strings.ps_envstr = envp;
 		minix_ps_strings.ps_argvstr = argv;
 		minix_ps_strings.ps_nargvstr = argc;

lib/libm/Makefile

@@ -104,7 +104,7 @@ WARNS?=4
 .endif
 
 WARNS?=4
-#i LSC MINIX, do not compile yet with -Werror... 
+# LSC MINIX, do not compile yet with -Werror...
 NOGCCERROR=yes
 
 .PATH:	${.CURDIR}/man

lib/libm/complex/Makefile.inc

@@ -11,7 +11,11 @@ SRCS+= casin.c cacos.c catan.c casinh.c cacosh.c catanh.c
 SRCS+= csqrtf.c cexpf.c clogf.c cpowf.c
 SRCS+= cephes_subrf.c csinf.c ccosf.c ctanf.c csinhf.c ccoshf.c ctanhf.c
 SRCS+= casinf.c cacosf.c catanf.c casinhf.c cacoshf.c catanhf.c
+.if defined(__MINIX)
+SRCS+= cproj.c cprojf.c
+.else
 SRCS+= cproj.c cprojf.c cprojl.c
+.endif # defined(__MINIX)
 
 MAN+= cabs.3 cacos.3 cacosh.3 carg.3 casin.3 casinh.3 catan.3 catanh.3
 MAN+= ccos.3 ccosh.3 cexp.3 cimag.3 clog.3 conj.3 cpow.3 cproj.3 creal.3