diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index a78e105dd..7189375ec 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -14,7 +14,7 @@ on:
 jobs:
   build:
     name: "Run Unit tests"
-    runs-on: [ubuntu-20.04]
+    runs-on: [ubuntu-20.04, ubuntu-18.04]
     defaults:
       run:
         shell: bash
diff --git a/gef.py b/gef.py
index 2912e6de4..b3e4f53cf 100644
--- a/gef.py
+++ b/gef.py
@@ -822,7 +822,7 @@ def align_data_address(self):
         else:
             # Generic case:
             # https://elixir.bootlin.com/glibc/glibc-2.26/source/sysdeps/generic/malloc-alignment.h#L22
-            __alignof__long_double = int(safe_parse_and_eval("_Alignof(long double)"))
+            __alignof__long_double = int(safe_parse_and_eval("_Alignof(long double)") or 0x10)
             malloc_alignment = max(__alignof__long_double, 2 * self.ptrsize)
 
         ceil = lambda n: int(-1 * n // 1 * -1)