diff --git a/groups/221.native_packages_dev.group b/groups/221.native_packages_dev.group
index 2ebbc07..c0e3610 100644
--- a/groups/221.native_packages_dev.group
+++ b/groups/221.native_packages_dev.group
@@ -71,8 +71,8 @@ patch patchutils perl posix_cc python2 python3 ruby sbsigntools smallbasic tk")"
 : ${PKG_LUNIX_IN_TREE:=1};
 : ${PKG_LUNIX_MAKEFLAGS_BUILD:="all5.3 libdir=${PREFIX_NATIVE}/lib"};
 : ${PKG_LUNIX_MAKEFLAGS_INSTALL_EXTRA:="libdir=lib"};
-: ${PKG_M4_SHA256SUM:=f2c1e86ca0a404ff281631bdc8377638992744b175afb806e25871a24a934e07};
-: ${PKG_M4_VERSION:=1.4.18};
+: ${PKG_M4_SHA256SUM:=63aede5c6d33b6d9b13511cd0be2cac046f2e70fd0a07aa9573a04a82783af96};
+: ${PKG_M4_VERSION:=1.4.19};
 : ${PKG_M4_URL:=https://ftp.gnu.org/gnu/m4/m4-${PKG_M4_VERSION}.tar.xz};
 : ${PKG_MAKE_SHA256SUM:=e40b8f018c1da64edd1cc9a6fce5fa63b2e707e404e20cad91fbae337c98a5b7};
 : ${PKG_MAKE_VERSION:=4.2.1};
diff --git a/midipix.env b/midipix.env
index f883cfa..13f330e 100644
--- a/midipix.env
+++ b/midipix.env
@@ -313,6 +313,7 @@ gl_cv_func_select_detects_ebadf=yes
 gl_cv_func_setenv_works=yes
 gl_cv_func_signbit_gcc=yes
 gl_cv_func_signbit=yes
+gl_cv_func_signbit_builtins=yes
 gl_cv_func_sleep_works=yes
 gl_cv_func_snprintf_directive_n=yes
 gl_cv_func_snprintf_retval_c99=yes