diff --git a/steps-guix/gawk-4.2.1/patches/fix-strtod-prototype.patch b/steps-guix/gawk-4.2.1/patches/fix-strtod-prototype.patch
new file mode 100644
index 00000000..c539dcc6
--- /dev/null
+++ b/steps-guix/gawk-4.2.1/patches/fix-strtod-prototype.patch
@@ -0,0 +1,15 @@
+SPDX-License-Identifier: GPL-3.0-or-later
+
+Fix legacy strtod declaration to match modern libc prototype.
+
+--- gawk-4.2.1/node.c
++++ gawk-4.2.1/node.c
+@@ -62,7 +62,7 @@
+ #endif
+ 
+ #ifndef __STDC__
+-	extern double strtod();
++	extern double strtod(const char *, char **);
+ #endif
+ 
+ /* r_force_number --- force a value to be numeric */