diff --git a/var/spack/repos/builtin/packages/gettext/package.py b/var/spack/repos/builtin/packages/gettext/package.py
index b528e8a8b07..de077821f26 100644
--- a/var/spack/repos/builtin/packages/gettext/package.py
+++ b/var/spack/repos/builtin/packages/gettext/package.py
@@ -58,6 +58,13 @@ class Gettext(AutotoolsPackage, GNUMirrorPackage):
     patch("nvhpc-export-symbols.patch", when="%nvhpc")
     patch("nvhpc-long-width.patch", when="%nvhpc")
 
+    # Apply this only where we know that the system libc is glibc, be very careful:
+    @when("@:0.21.0 target=ppc64le:")
+    def patch(self):
+        for fn in ("gettext-tools/gnulib-lib/cdefs.h", "gettext-tools/libgrep/cdefs.h"):
+            with open(fn, "w") as f:
+                f.write("#include <sys/cdefs.h>\n")
+
     @classmethod
     def determine_version(cls, exe):
         gettext = Executable(exe)