altcross.sh: disable libsanitizer to avoid build error

libsanitizer wants limits.h, which is a part of compiler. However
the compiler hasn't been installed yet, since we are building its
runtime. Disable libsanitizer to avoid the problem.

TODO: Perhaps there's a special target to build an install compiler
headers only. Figure it out and re-enable libsanitizer.

altcross.sh

@@ -67,6 +67,17 @@ make -j$(nproc)
 make -j$(nproc) install DESTDIR="$INSTALLDIR"
 
 # gcc 
+# Disable libsanitizer to avoid the build failure:
+#
+# ../../../../../src/gcc/libsanitizer/asan/asan_linux.cpp: In function ‘void __asan::AsanCheckIncompatibleRT()’:
+# ../../../../../src/gcc/libsanitizer/asan/asan_linux.cpp:217:21: error: ‘PATH_MAX’ was not declared in this scope
+#  217 |       char filename[PATH_MAX];
+#      |                     ^~~~~~~~
+# ../../../../../src/gcc/libsanitizer/asan/asan_linux.cpp:218:35: error: ‘filename’ was not declared in this scope; did you mean ‘fileno’?
+#  218 |       MemoryMappedSegment segment(filename, sizeof(filename));
+#      |                                   ^~~~~~~~
+#      |                                   fileno
+
 cd "$BUILDDIR/obj_gcc"
 ../../src/gcc/configure \
 	--prefix= \
@@ -76,6 +87,7 @@ cd "$BUILDDIR/obj_gcc"
 	--with-sysroot="$SYSROOT" \
 	--with-build-sysroot="$SYSROOTDIR" \
 	--with-gcc-major-version-only \
+	--disable-libsanitizer \
 	--disable-multilib
 
 # compiler only