x86_64 and x32 fail to build

[Alexander Monakov <amonakov@ispras.ru>]

After recent commits musl fails to build for x86_64 and x32.

When configuring on x86_64, configure mistakenly thinks the host compiler is
going to produce code for x32.  This is because __ILP32__ check wrongly
succeeds.  That is because it's looking for compilation failure due to #error
preprocessor directive, but compilation instead fails because vis.h is not
found (-include vis.h is added to CFLAGS with -I giving the path to it).  I
have used the following patch to proceed with the build:

diff --git a/configure b/configure
index 0e39694..cebee09 100755
--- a/configure
+++ b/configure
@@ -440,7 +440,7 @@ printf "%s\n" "$visibility"
 fi
 
 if test "x$visibility" == xyes ; then
-CFLAGS_AUTO="$CFLAGS_AUTO -include vis.h"
+CFLAGS_AUTO="$CFLAGS_AUTO  -I./arch/$ARCH -I src/internal -I./include -include vis.h"
 CFLAGS_AUTO="${CFLAGS_AUTO# }"
 fi
 

Would be nice to rework trycppif configure function to be robust against this
kind of failures.

When targeting x32, build fails due to "jmp" instruction expecting a 64-bit
argument.  At least the following change is needed, but I'm not sure it's
sufficient: the register should be zero-extended, not sign-extended:

diff --git a/arch/x32/reloc.h b/arch/x32/reloc.h
index 7c72d26..492fbf1 100644
--- a/arch/x32/reloc.h
+++ b/arch/x32/reloc.h
@@ -23,4 +23,4 @@
 #define REL_TPOFF       R_X86_64_TPOFF64
 
 #define CRTJMP(pc,sp) __asm__ __volatile__( \
-	"mov %1,%%esp ; jmp *%0" : : "r"(pc), "r"(sp) : "memory" )
+	"mov %1,%%esp ; jmp *%q0" : : "r"(pc), "r"(sp) : "memory" )


Alexander