e2fsck: Don't use e2fsck_global_ctx unless HAVE_SIGNAL_H

Program received signal SIGSEGV, Segmentation fault.
0x56577382 in e2fsck_set_bitmap_type (fs=0x5658c2b8, default_type=2, profile_name=0x56580e12 "default", old_type=0x0) at external/e2fsprogs/e2fsck/util.c:797
797             profile_get_uint(e2fsck_global_ctx->profile, "bitmaps",

e2fsck_global_ctx is only ever initialized in unix.c PRS()
if HAVE_SIGNAL_H is defined.

Change-Id: Ic93fb8d9114054f7bf8512c622b2fb9b2ae60584
Signed-off-by: JP Abgrall <jpa@google.com>

e2fsck/util.c

@@ -794,11 +794,15 @@ void e2fsck_set_bitmap_type(ext2_filsys fs, unsigned int default_type,
 
 	if (old_type)
 		*old_type = fs->default_bitmap_type;
+#ifdef HAVE_SIGNAL_H
 	profile_get_uint(e2fsck_global_ctx->profile, "bitmaps",
 			 profile_name, 0, default_type, &type);
 	profile_get_uint(e2fsck_global_ctx->profile, "bitmaps",
 			 "all", 0, type, &type);
 	fs->default_bitmap_type = type ? type : default_type;
+#else
+	fs->default_bitmap_type = default_type;
+#endif
 }
 
 errcode_t e2fsck_allocate_inode_bitmap(ext2_filsys fs, const char *descr,