Check for headers in builddir first, in check-*.sh

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=103346

src/check-c-linkage-decls.sh

diff --git a/src/check-c-linkage-decls.sh b/src/check-c-linkage-decls.sh
index b10310f..cd55086 100755
--- a/src/check-c-linkage-decls.sh
+++ b/src/check-c-linkage-decls.sh
@@ -11,14 +11,14 @@
 
 
 for x in $HBHEADERS; do
-	test -f $srcdir/$x && x=$srcdir/$x
+	test -f "$srcdir/$x" -a ! -f "$x" && x="$srcdir/$x"
 	if ! grep -q HB_BEGIN_DECLS "$x" || ! grep -q HB_END_DECLS "$x"; then
 		echo "Ouch, file $x does not have HB_BEGIN_DECLS / HB_END_DECLS, but it should"
 		stat=1
 	fi
 done
 for x in $HBSOURCES; do
-	test -f $srcdir/$x && x=$srcdir/$x
+	test -f "$srcdir/$x" -a ! -f "$x" && x="$srcdir/$x"
 	if grep -q HB_BEGIN_DECLS "$x" || grep -q HB_END_DECLS "$x"; then
 		echo "Ouch, file $x has HB_BEGIN_DECLS / HB_END_DECLS, but it shouldn't"
 		stat=1

src/check-externs.sh

diff --git a/src/check-externs.sh b/src/check-externs.sh
index 7f0e321..a6de375 100755
--- a/src/check-externs.sh
+++ b/src/check-externs.sh
@@ -13,7 +13,7 @@
 echo 'Checking that all public symbols are exported with HB_EXTERN'
 
 for x in $HBHEADERS; do
-	test -f "$srcdir/$x" && x="$srcdir/$x"
+	test -f "$srcdir/$x" -a ! -f "$x" && x="$srcdir/$x"
 	$EGREP -B1 -n '^hb_' /dev/null "$x" |
 	$EGREP -v '(^--|:hb_|-HB_EXTERN )' -A1
 done |

src/check-header-guards.sh

diff --git a/src/check-header-guards.sh b/src/check-header-guards.sh
index 09c5ea8..355d81b 100755
--- a/src/check-header-guards.sh
+++ b/src/check-header-guards.sh
@@ -10,7 +10,7 @@
 test "x$HBSOURCES" = x && HBSOURCES=`cd "$srcdir"; find . -maxdepth 1 -name 'hb-*.cc' -or -name 'hb-*.hh'`
 
 for x in $HBHEADERS $HBSOURCES; do
-	test -f "$srcdir/$x" && x="$srcdir/$x"
+	test -f "$srcdir/$x" -a ! -f "$x" && x="$srcdir/$x"
 	echo "$x" | grep -q '[^h]$' && continue;
 	xx=`echo "$x" | sed 's@.*/@@'`
 	tag=`echo "$xx" | tr 'a-z.-' 'A-Z_'`

src/check-includes.sh

diff --git a/src/check-includes.sh b/src/check-includes.sh
index 902f235..37e372d 100755
--- a/src/check-includes.sh
+++ b/src/check-includes.sh
@@ -13,7 +13,7 @@
 echo 'Checking that public header files #include "hb-common.h" or "hb.h" first (or none)'
 
 for x in $HBHEADERS; do
-	test -f "$srcdir/$x" && x="$srcdir/$x"
+	test -f "$srcdir/$x" -a ! -f "$x" && x="$srcdir/$x"
 	grep '#.*\<include\>' "$x" /dev/null | head -n 1
 done |
 grep -v '"hb-common[.]h"' |
@@ -26,7 +26,7 @@
 echo 'Checking that source files #include "hb-*private.hh" first (or none)'
 
 for x in $HBSOURCES; do
-	test -f "$srcdir/$x" && x="$srcdir/$x"
+	test -f "$srcdir/$x" -a ! -f "$x" && x="$srcdir/$x"
 	grep '#.*\<include\>' "$x" /dev/null | grep -v 'include _' | head -n 1
 done |
 grep -v '"hb-.*private[.]hh"' |