diff --git a/packages/conf-gmp-powm-sec/conf-gmp-powm-sec.3/opam b/packages/conf-gmp-powm-sec/conf-gmp-powm-sec.3/opam
index c9ab8724b23..9640888b7ef 100644
--- a/packages/conf-gmp-powm-sec/conf-gmp-powm-sec.3/opam
+++ b/packages/conf-gmp-powm-sec/conf-gmp-powm-sec.3/opam
@@ -4,7 +4,8 @@ homepage: "http://gmplib.org/"
 bug-reports: "https://github.com/ocaml/opam-repository/issues"
 license: "GPL-1.0-or-later"
 build: [
-  ["sh" "-exc" "$(ocamlc -config-var c_compiler) -c $CFLAGS -I/usr/local/include test.c"] {os != "macos"}
+  ["sh" "-exc" "cc -c $CFLAGS -I/usr/local/include test.c"] {os != "macos" && os != "win32" }
+  ["sh" "-exc" "$(ocamlc -config-var c_compiler) -c $CFLAGS test.c"] {os = "win32"}
   [
     "sh"
     "-exc"
diff --git a/packages/conf-mingw-w64-gmp-i686/conf-mingw-w64-gmp-i686.1/opam b/packages/conf-mingw-w64-gmp-i686/conf-mingw-w64-gmp-i686.1/opam
index 020f429acf9..cb39b7bc75b 100644
--- a/packages/conf-mingw-w64-gmp-i686/conf-mingw-w64-gmp-i686.1/opam
+++ b/packages/conf-mingw-w64-gmp-i686/conf-mingw-w64-gmp-i686.1/opam
@@ -2,6 +2,7 @@ opam-version: "2.0"
 synopsis: "Virtual package for libgmp on i686 mingw-w64 (32-bit x86)"
 description: "Ensures the i686 version of libgmp for the mingw-w64 project is available"
 maintainer: "David Allsopp <david@tarides.com>"
+authors: "David Allsopp <david@tarides.com>"
 license: "GPL-1.0-or-later"
 homepage: "http://gmplib.org/"
 bug-reports: "https://github.com/ocaml/opam-repository/issues"
diff --git a/packages/conf-mingw-w64-gmp-x86_64/conf-mingw-w64-gmp-x86_64.1/opam b/packages/conf-mingw-w64-gmp-x86_64/conf-mingw-w64-gmp-x86_64.1/opam
index 9bed11ddb16..b401bf655c1 100644
--- a/packages/conf-mingw-w64-gmp-x86_64/conf-mingw-w64-gmp-x86_64.1/opam
+++ b/packages/conf-mingw-w64-gmp-x86_64/conf-mingw-w64-gmp-x86_64.1/opam
@@ -2,6 +2,7 @@ opam-version: "2.0"
 synopsis: "Virtual package for libgmp on x86_64 mingw-w64 (64-bit x86_64)"
 description: "Ensures the x86_64 version of libgmp for the mingw-w64 project is available"
 maintainer: "David Allsopp <david@tarides.com>"
+authors: "David Allsopp <david@tarides.com>"
 license: "GPL-1.0-or-later"
 homepage: "http://gmplib.org/"
 bug-reports: "https://github.com/ocaml/opam-repository/issues"