Makefile.inc: Fix build hang if file-size is run on empty string

Currently, if for some reason, the file-size command is called on an
empty string, the build will hang waiting for stdin input to cat.
Since wc accepts a file, this cat was unnecessary anyway.  Put the file
name in quotes so an empty string will result in calling wc on an
actual null file instead of just leaving the filename blank.  This
results in an error, and will probably halt the build.

BUG=214790407
TEST=Build default build.

Signed-off-by: Martin Roth <martin.roth@amd.corp-partner.google.com>
Change-Id: I3dacf1968ed897a8ebd00f95583c2f254a7fb55a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/67263
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/Makefile.inc b/Makefile.inc
index 0dd4864..0ed205f 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -153,7 +153,7 @@
 int-eq=$(if $(filter 1,$(words $1)),$(strip $1),$(shell expr $(call _toint,$(word 1,$1)) = $(call _toint,$(word 2,$1))))
 int-align=$(shell A=$(call _toint,$1) B=$(call _toint,$2); expr $$A + \( \( $$B - \( $$A % $$B \) \) % $$B \) )
 int-align-down=$(shell A=$(call _toint,$1) B=$(call _toint,$2); expr $$A - \( $$A % $$B \) )
-file-size=$(strip $(shell cat $1 | wc -c))
+file-size=$(strip $(shell wc -c "$1" | cut -f 1 -d ' '))
 tolower=$(shell echo '$1' | tr '[:upper:]' '[:lower:]')
 toupper=$(shell echo '$1' | tr '[:lower:]' '[:upper:]')
 ws_to_under=$(shell echo '$1' | tr ' \t' '_')