diff --git a/sci-libs/cgnslib/cgnslib-4.5.0.ebuild b/sci-libs/cgnslib/cgnslib-4.5.0.ebuild
index fda3e085bea47..712c25a49978a 100644
--- a/sci-libs/cgnslib/cgnslib-4.5.0.ebuild
+++ b/sci-libs/cgnslib/cgnslib-4.5.0.ebuild
@@ -44,6 +44,7 @@ REQUIRED_USE="
 
 PATCHES=(
 	"${FILESDIR}"/${PN}-4.5.0-rpath.patch
+	"${FILESDIR}"/${PN}-4.5.0-tk-internal.patch
 )
 
 pkg_setup() {
@@ -66,10 +67,12 @@ src_configure() {
 	filter-lto
 
 	# Needed for uses an internal header (bug #934122)
-	local tk_ver=$(best_version dev-lang/tk)
-	tk_ver=${tk_ver#dev-lang/tk-}
-	tk_ver=$(ver_cut 1-2 ${tk_ver})
-	append-cppflags -I"${ESYSROOT}/usr/$(get_libdir)/tk${tk_ver}/include/generic"
+	if use tools ; then
+		local tk_ver=$(best_version dev-lang/tk)
+		tk_ver=${tk_ver#dev-lang/tk-}
+		tk_ver=$(ver_cut 1-2 ${tk_ver})
+		append-cppflags -I"${ESYSROOT}/usr/$(get_libdir)/tk${tk_ver}/include/generic"
+	fi
 
 	local mycmakeargs=(
 		-DCGNS_BUILD_SHARED=ON
diff --git a/sci-libs/cgnslib/files/cgnslib-4.5.0-tk-internal.patch b/sci-libs/cgnslib/files/cgnslib-4.5.0-tk-internal.patch
new file mode 100644
index 0000000000000..fb05b0aeb6f36
--- /dev/null
+++ b/sci-libs/cgnslib/files/cgnslib-4.5.0-tk-internal.patch
@@ -0,0 +1,12 @@
+https://bugs.gentoo.org/959272
+--- a/src/cgnstools/tkogl/tkogl.c
++++ b/src/cgnstools/tkogl/tkogl.c
+@@ -25,7 +25,7 @@
+ #if ! defined(__WIN32__) && ! defined(_WIN32)
+ /* For TkWmAddToColormapWindows. */
+ #define _TKPORT /* Typical installations cannot find tkPort.h. */
+-#include <tk-private/generic/tkInt.h>
++#include <tkInt.h>
+ #endif
+ 
+ #ifndef CONST