diff --git a/meson.build b/meson.build
index e84251fbf..fc61b02ee 100644
--- a/meson.build
+++ b/meson.build
@@ -532,13 +532,23 @@ foreach f : functions
   endif
 endforeach
 
-# Check that stpcpy() is usable; must use header
-if cc.has_function('stpcpy', prefix : '#include <string.h>')
+# Check that stpcpy() is usable; must use header.
+# cc.has_function() in some cases (clang, gcc 10+) assumes that if the
+# compiler provides a builtin of the same name that the function exists, while
+# it's in fact not provided by any header or library. This is true for
+# stpcpy() on Windows using clang and gcc as well as posix_memalign() using
+# gcc on Windows. Skip these checks on Windows for now to avoid false
+# positives. See https://github.com/mesonbuild/meson/pull/7116,
+# https://github.com/mesonbuild/meson/issues/3672 and
+# https://github.com/mesonbuild/meson/issues/5628.
+# FIXME: Once meson no longer returns success for stpcpy() and
+# posix_memalign() on Windows using GCC and clang we can remove this.
+if host_system != 'windows' and cc.has_function('stpcpy', prefix : '#include <string.h>')
   glib_conf.set('HAVE_STPCPY', 1)
 endif
 
 # Check that posix_memalign() is usable; must use header
-if cc.has_function('posix_memalign', prefix : '#include <stdlib.h>')
+if host_system != 'windows' and cc.has_function('posix_memalign', prefix : '#include <stdlib.h>')
   glib_conf.set('HAVE_POSIX_MEMALIGN', 1)
 endif