Add test case for source patching.

.gitignore

@@ -2,15 +2,19 @@ downloads/
 archives/
 *.orig
 *.swp
+venv*/
+.venv/
 
 # lib_check downloads these
 *-stamp
+arch_tmp/
 arb*/
 bzip2*/
 cfitsio/
 flex*/
 freetype*/
 giflib*/
+harfbuzz*/
 hdf5*/
 jpeg*/
 lcms2*/

common_utils.sh

@@ -290,11 +290,11 @@ function fetch_unpack {
         rsync --delete -ah * ..)
 
     # If a patch exists, apply it
-    if [ -e "${PATCH_DIR}/${name}-${version}.patch" ]; then
+    if [ -e "$(pwd)/${PATCH_DIR}/${archive_fname}.patch" ]; then
         # The arch_tmp folder will contain the name of folder that was just
         # unpacked from the archive. Apply the patch in that directory.
         local package_dir=$(ls -1c arch_tmp)
-        patch --force -i "${PATCH_DIR}/${name}-${version}.patch" -d $package_dir
+        patch --force -i "$(pwd)/${PATCH_DIR}/${archive_fname}.patch" -d $package_dir
     fi
 }
 

tests/patches/harfbuzz-2.7.4.tar.xz.patch

@@ -0,0 +1,11 @@
+# This is a completely cosmetic patch to validate that source patching works as expected.
+#
+diff -ur harfbuzz-2.7.4-orig/README harfbuzz-2.7.4/README
+--- harfbuzz-2.7.4-orig/README	2024-12-12 09:23:15
++++ harfbuzz-2.7.4/README	2024-12-12 09:23:02
+@@ -13,3 +13,5 @@
+ For test execution, see https://github.com/harfbuzz/harfbuzz/blob/master/TESTING.md
+
+ Documentation: https://harfbuzz.github.io
++
++Harfbuzz has been patched by multibuild

tests/test_library_builders.sh

@@ -21,8 +21,10 @@ source tests/utils.sh
 
 start_spinner
 
+PATCH_DIR=tests/patches
 fetch_unpack https://github.com/harfbuzz/harfbuzz/releases/download/2.7.4/harfbuzz-2.7.4.tar.xz
 [ -d harfbuzz-2.7.4 ] || ingest ".tar.xz should have been unpacked"
+[ -n "$(grep 'Harfbuzz has been patched by multibuild' harfbuzz-2.7.4/README)" ] || ingest "Harfbuzz should have been patched"
 
 suppress build_bzip2
 suppress build_openssl