addition of instant assembler by Alan Cashin

Instant 6502 Assembler was originally written for the KIM-1 and
reconstructed using the acme assembler. This is a port to the ca65 as
assembler and Sorbus as platform. The port is elegant in a way that the
routines called by instant assembler in the KIM-1 have been reimplemented
for the Sorbus.

So by flipping a switch in the source code, the KIM-1 version can still
be assembled. (Theoretically, since it was not tried.)

Signed-off-by: Sven Oliver Moll <svolli@svolli.de>

src/65c02/CMakeLists.txt

@@ -169,6 +169,11 @@ add_executable(int-test
    )
 target_type(int-test sx4)
 
+add_executable(inst-ass
+   native_sx4/inst-ass.s
+   )
+target_type(inst-ass sx4)
+
 add_executable(1sthello
    native_sx4/a1hello.s
    )