Verify mandatory Ruby patches exist

patches/ruby/mandatory_patches

@@ -0,0 +1 @@
+thread-memory-allocations

scripts/install-ruby

@@ -46,10 +46,23 @@ function build_common() {
     rm ruby.tar.gz
     cd /usr/src/ruby
 
+    # Process patch files
+    local ruby_version=$(cut -d '.' -f 1,2 <<< $RUBY_VERSION)
+    local patchdir="/patches/ruby/${ruby_version}"
+
+    # Verify mandatory patches
+    while read -r patchname; do
+      local patchfile="${patchdir}/${patchname}.patch"
+      if [[ ! -f "${patchfile}" ]]; then
+        echo "!! Missing mandatory patch ${patchname}"
+        echo "!! Make sure ${patchfile} exists before proceeding."
+        exit 1
+      fi
+    done < "/patches/ruby/mandatory_patches"
+
     # Apply patches
-    ruby_version=`cut -d '.' -f 1,2 <<< $RUBY_VERSION`
-    if [[ -d "/patches/ruby/$ruby_version" ]]; then
-      for i in "/patches/ruby/$ruby_version"/*.patch; do
+    if [[ -d "${patchdir}" ]]; then
+      for i in "${patchdir}"/*.patch; do
         echo "$i..."
         patch -p1 -i "$i"
       done