diff --git a/pkgs/tools/text/groff/default.nix b/pkgs/tools/text/groff/default.nix
index 575b89ba318a..166ec1b28036 100644
--- a/pkgs/tools/text/groff/default.nix
+++ b/pkgs/tools/text/groff/default.nix
@@ -5,6 +5,7 @@
 , autoreconfHook
 , pkg-config
 , texinfo
+, bash
 }:
 
 stdenv.mkDerivation rec {
@@ -31,7 +32,11 @@ stdenv.mkDerivation rec {
     })
   ];
 
-  postPatch = lib.optionalString (psutils != null) ''
+  postPatch = ''
+    # BASH_PROG gets replaced with a path to the build bash which doesn't get automatically patched by patchShebangs
+    substituteInPlace contrib/gdiffmk/gdiffmk.sh \
+      --replace "@BASH_PROG@" "/bin/sh"
+  '' + lib.optionalString (psutils != null) ''
     substituteInPlace src/preproc/html/pre-html.cpp \
       --replace "psselect" "${psutils}/bin/psselect"
   '' + lib.optionalString (netpbm != null) ''
@@ -45,7 +50,8 @@ stdenv.mkDerivation rec {
       --replace "@PNMTOPS_NOSETPAGE@" "${lib.getBin netpbm}/bin/pnmtops -nosetpage"
   '';
 
-  buildInputs = [ ghostscript psutils netpbm perl ];
+  strictDeps = true;
+  buildInputs = [ ghostscript psutils netpbm perl bash ];
   nativeBuildInputs = [ autoreconfHook pkg-config texinfo ];
 
   # Builds running without a chroot environment may detect the presence