Add archlinux CI + Silence compilation warnings on new libxml2 (#93)

* Add archlinux CI

Copied from #91

* See if this allows me to install a specific version

* fix version

* Apply casting to do away the const explicitly

.github/workflows/ci.yml

@@ -5,7 +5,7 @@ on:
       - master
 
 jobs:
-  build:
+  ubuntu:
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -32,3 +32,25 @@ jobs:
           check-latest: true
       - name: Test 
         run: go test ./...
+  archlinux:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go: [ '1.21' ]
+    container:
+      image: archlinux:latest
+    name: "Test [ Arch Linux + Go ${{ matrix.go }} ]"
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set Up Arch Linux
+        run: |
+          pacman -Syy --noconfirm
+          pacman -Syu --noconfirm
+          pacman -S --noconfirm base-devel 
+          pacman -S --noconfirm libxml2=2.12.0
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: ${{ matrix.go }}
+      - name: Test
+        run: go test ./...

clib/clib.go

@@ -58,13 +58,13 @@ static inline void MY_xmlFree(void *p) {
 // Macro wrapper function. cgo cannot detect function-like macros,
 // so this is how we avoid it
 static inline xmlError* MY_xmlLastError() {
-	return xmlGetLastError();
+	return (xmlError*) xmlGetLastError();
 }
 
 // Macro wrapper function. cgo cannot detect function-like macros,
 // so this is how we avoid it
 static inline xmlError* MY_xmlCtxtLastError(void *ctx) {
-	return xmlCtxtGetLastError(ctx);
+	return (xmlError*) xmlCtxtGetLastError(ctx);
 }
 
 // Change xmlIndentTreeOutput global, return old value, so caller can