Make directory for shared-GC libraries at build

.github/workflows/ubuntu.yml

@@ -35,7 +35,6 @@ jobs:
             configure: '--enable-shared --enable-load-relative'
           - test_task: check
             shared_gc: true
-            shared_gc_dir: '/home/runner/ruby_gc'
             configure: '--with-shared-gc=/home/runner/ruby_gc'
           - test_task: test-bundler-parallel
             timeout: 50
@@ -99,9 +98,8 @@ jobs:
         if: ${{ matrix.test_task == 'test-bundled-gems' }}
 
       - name: Build shared GC
-        run: >
-          echo "RUBY_GC_LIBRARY=librubygc.default.so" >> $GITHUB_ENV &&
-          mkdir ${{ matrix.shared_gc_dir }} &&
+        run: |
+          echo "RUBY_GC_LIBRARY=librubygc.default.so" >> $GITHUB_ENV
           make shared-gc SHARED_GC=default
         if: ${{ matrix.shared_gc }}
 

common.mk

@@ -1914,8 +1914,9 @@ shared-gc: probes.h
 		exit 1; \
 	else \
 		echo generating $(shared_gc_dir)librubygc.$(SHARED_GC).$(SOEXT); \
-		$(LDSHARED) -I$(srcdir)/include -I$(srcdir) -I$(arch_hdrdir) $(XDLDFLAGS) $(cflags) -DBUILDING_SHARED_GC -fPIC -o $(shared_gc_dir)librubygc.$(SHARED_GC).$(SOEXT) $(srcdir)/gc/$(SHARED_GC).c; \
 	fi
+	$(Q) $(MAKEDIRS) $(shared_gc_dir)
+	$(Q) $(LDSHARED) -I$(srcdir)/include -I$(srcdir) -I$(arch_hdrdir) $(XDLDFLAGS) $(cflags) -DBUILDING_SHARED_GC -fPIC -o $(shared_gc_dir)librubygc.$(SHARED_GC).$(SOEXT) $(srcdir)/gc/$(SHARED_GC).c
 
 help: PHONY
 	$(MESSAGE_BEGIN) \