Update gitignore with patterns for generated files

tests/regression/.gitignore

@@ -4,4 +4,23 @@
 
 # Ignore tmp directories in this folder and below
 
-**/tmp/
\ No newline at end of file
+**/tmp/
+**/build/
+
+*/*generated
+*/generated*
+*/*.adb
+*/*.ads
+*/*.ali
+*/*.o
+*/*.gcno
+*/*.c
+*/*.h
+*/*.cfg
+*/*.idx
+*/*.wrn
+*/*.gpr
+*/*.sh
+*/test_ada
+*/test_c
+*/*.gcda
\ No newline at end of file