package/assimp: needs gcc >= 7

Fixes:
http://autobuild.buildroot.net/results/d6c/d6caf3c2c0fd670e70950d3e89629df39f8ce596/

After adding various fixes for the autobuilder error and subsequent
build errors this build error can only be fixed by using gcc >= 7:

output/build/assimp-5.2.5/code/AssetLib/Obj/ObjFileParser.cpp:55:23:
 fatal error: string_view: No such file or directory

Usage of string_view was added in version 5.2.5 by upstream commit
https://github.com/assimp/assimp/commit/f6bcb160d08af267778fbc59b480ce5d9c52c92c
which was added to buildroot by commit
7d843d9cc0064d6690cfc000e579f575e2c0cc4d

Removed BR2_TOOLCHAIN_HAS_GCC_BUG_64735 which is only valid for gcc < 7

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/assimp/Config.in

@@ -2,7 +2,7 @@ config BR2_PACKAGE_ASSIMP
 	bool "assimp"
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_USE_WCHAR
-	depends on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735 # exception_ptr
+	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_7
 	select BR2_PACKAGE_ZLIB
 	select BR2_PACKAGE_ZLIB_FORCE_LIBZLIB
 	help
@@ -14,8 +14,6 @@ config BR2_PACKAGE_ASSIMP
 
 	  http://www.assimp.org
 
-comment "assimp needs a toolchain w/ C++, wchar"
-	depends on !BR2_INSTALL_LIBSTDCPP || !BR2_USE_WCHAR
-
-comment "assimp needs exception_ptr"
-	depends on BR2_TOOLCHAIN_HAS_GCC_BUG_64735
+comment "assimp needs a toolchain w/ C++, wchar, gcc >= 7"
+	depends on !BR2_INSTALL_LIBSTDCPP || !BR2_USE_WCHAR \
+		|| !BR2_TOOLCHAIN_GCC_AT_LEAST_7