LDC: Don't keep around temporary object files for static libs

This was a workaround for older LDC versions. Since LDC v1.25,
`-cleanup-obj` implies that the temporary object files are placed
into a unique temp directory (per compiler invocation), so that
object file collisions across parallel dub invocations cannot happen
anymore.

source/dub/compilers/ldc.d

@@ -113,9 +113,6 @@ config    /etc/ldc2.conf (x86_64-pc-linux-gnu)
 					settings.addDFlags(t[1]);
 		}
 
-		// since LDC always outputs multiple object files, avoid conflicts by default
-		settings.addDFlags("--oq", format("-od=%s/obj", settings.targetPath));
-
 		if (!(fields & BuildSetting.versions)) {
 			settings.addDFlags(settings.versions.map!(s => "-d-version="~s)().array());
 			settings.versions = null;
@@ -234,7 +231,9 @@ config    /etc/ldc2.conf (x86_64-pc-linux-gnu)
 			case TargetType.executable: break;
 			case TargetType.library:
 			case TargetType.staticLibrary:
-				settings.addDFlags("-lib");
+				// -oq: name object files uniquely (so the files don't collide)
+				// -cleanup-obj: remove object files after archiving to static lib, and put them in a unique temp directory
+				settings.addDFlags("-lib", "-oq", "-cleanup-obj");
 				break;
 			case TargetType.dynamicLibrary:
 				settings.addDFlags("-shared");

test/removed-dub-obj.sh

@@ -3,19 +3,13 @@
 . $(dirname "${BASH_SOURCE[0]}")/common.sh
 cd ${CURR_DIR}/removed-dub-obj
 
-DUB_CACHE_PATH="$HOME/.dub/cache/removed-dub-obj/"
+DUB_CACHE_PATH="$HOME/.dub/cache/removed-dub-obj"
 
-rm -rf $DUB_CACHE_PATH
+rm -rf "$DUB_CACHE_PATH"
 
 ${DUB} build --compiler=${DC}
 
-[ -d "$DUB_CACHE_PATH/obj" ] && die $LINENO "$DUB_CACHE_PATH/obj was found"
+[ -d "$DUB_CACHE_PATH" ] || die $LINENO "$DUB_CACHE_PATH not found"
 
-if [[ ${DC} == *"ldc"* ]]; then
-    if [ ! -f $DUB_CACHE_PATH/~master/build/library-*/obj/test.o* ]; then
-        ls -lR $DUB_CACHE_PATH
-        die $LINENO '$DUB_CACHE_PATH/~master/build/library-*/obj/test.o* was not found'
-    fi
-fi
-
-exit 0
+numObjectFiles=$(find "$DUB_CACHE_PATH" -type f -iname '*.o*' | wc -l)
+[ "$numObjectFiles" -eq 0 ] || die $LINENO "Found left-over object files in $DUB_CACHE_PATH"