Undefined jd_tt in example, and workflow to check example compilation

.github/workflows/example.yml

@@ -0,0 +1,24 @@
+name: Example
+
+on: 
+  push:
+    paths:
+      - 'examples/**'
+      - '.github/workflows/example.yml'
+
+jobs:
+
+  build:
+    name: Build library
+
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Compile example.c
+      run: |
+        cd examples
+        gcc -c -Wall -Werror -I ../include example.c 
+
+      
+   

examples/example.c

@@ -103,6 +103,7 @@ int main(void) {
 
   // Establish time arguments.
   jd_utc = julian_date(2008, 4, 24, 10.605);
+  jd_tt = jd_utc + ((double) leap_secs + 32.184) / 86400.0;
   jd_ut1 = jd_utc + ut1_utc / 86400.0;
   delta_t = get_ut1_to_tt(leap_secs, ut1_utc);