x11-libs/gtk-fortran: add USE="static-libs" conditional patch

Closes: https://bugs.gentoo.org/781812

Signed-off-by: Sergey Torokhov <torokhov-s-a@yandex.ru>

x11-libs/gtk-fortran/files/gtk-fortran-20.04_skip-static-build.patch

@@ -0,0 +1,32 @@
+diff -Naur a/src/CMakeLists.txt b/src/CMakeLists.txt
+--- a/src/CMakeLists.txt
++++ b/src/CMakeLists.txt
+@@ -73,17 +73,16 @@
+ endif()
+ 
+ #======================================================
+-# Defining the static and shared gtk-fortran libraries:
++# Defining the shared gtk-fortran libraries:
+ #======================================================
+ add_library(gtk-fortran_object OBJECT ${sources})
+ # To build position independent shared libraries:
+ set_property(TARGET gtk-fortran_object PROPERTY POSITION_INDEPENDENT_CODE TRUE)
+ 
+-add_library(gtk-fortran_static STATIC $<TARGET_OBJECTS:gtk-fortran_object>)
+ add_library(gtk-fortran_shared SHARED $<TARGET_OBJECTS:gtk-fortran_object>)
+ target_link_libraries(gtk-fortran_shared ${GTK_LIBRARIES})
+ 
+-set_target_properties(gtk-fortran_static gtk-fortran_shared PROPERTIES 
++set_target_properties(gtk-fortran_shared PROPERTIES 
+   OUTPUT_NAME ${gtk_V_fortran}
+   VERSION "0.1"
+   SOVERSION "0.1")
+@@ -131,7 +130,7 @@
+ #==================
+ # Files to install:
+ #==================
+-install(TARGETS gtk-fortran_static gtk-fortran_shared
++install(TARGETS gtk-fortran_shared
+   ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+   LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+   RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}

x11-libs/gtk-fortran/gtk-fortran-20.04.ebuild

@@ -18,7 +18,7 @@ LICENSE="GPL-3"
 SLOT="0"
 KEYWORDS="~amd64 ~x86"
 
-IUSE="examples high-level plplot"
+IUSE="examples high-level plplot static-libs"
 REQUIRED_USE="plplot? ( high-level )"
 
 RDEPEND="
@@ -43,6 +43,8 @@ src_prepare() {
 	sed -i -e "s:CMAKE_INSTALL_LIBDIR lib:CMAKE_INSTALL_LIBDIR $(get_libdir):" \
 	-e "s:    add_subdirectory(sketcher)::" CMakeLists.txt || die
 
+	use !static-libs && eapply "${FILESDIR}/${P}_skip-static-build.patch"
+
 	cmake_src_prepare
 }