Changed the OSU library "rename" to include the (nonstandard) ".tlef"
extension.  Also, noting that the check for names after "rename=" that
do not have file extensions is incomplete, added a case for "techlef"
and a catch-all case at the end.  This commit effectively implements
Amr's pull request #46, but in a slightly different way.

common/foundry_install.py

diff --git a/common/foundry_install.py b/common/foundry_install.py
index bc1ba45..1ee1503 100755
--- a/common/foundry_install.py
+++ b/common/foundry_install.py
@@ -834,16 +834,14 @@
 
                 if option[0] == 'verilog':
                     fileext = '.v'
-                elif option[0] == 'gds':
-                    fileext = '.gds'
                 elif option[0] == 'liberty' or option[0] == 'lib':
                     fileext = '.lib'
                 elif option[0] == 'spice' or option[0] == 'spi':
                     fileext = '.spice' if not ef_format else '.spi'
-                elif option[0] == 'cdl':
-                    fileext = '.cdl'
-                elif option[0] == 'lef':
+                elif option[0] == 'techlef':
                     fileext = '.lef'
+                else:
+                    fileext = '.' + option[0]
 
                 if newname:
                     if os.path.splitext(newname)[1] == '':

sky130/Makefile.in

diff --git a/sky130/Makefile.in b/sky130/Makefile.in
index ecdf5ea..dfb1c89 100644
--- a/sky130/Makefile.in
+++ b/sky130/Makefile.in
@@ -439,7 +439,7 @@
 	${RM} ${STAGING_PATH}/${SKY130A}/libs.ref/sky130_fd_sc_lp/verilog/*.*.v
 	# Install OSU digital standard cells.
 	${STAGE} -source ${SKYWATER_PATH} -target ${STAGING_PATH}/${SKY130A} \
-		-techlef %l/latest/lef/sky130_osu_sc.tlef rename=sky130_osu_sc_t18 \
+		-techlef %l/latest/lef/sky130_osu_sc.tlef rename=sky130_osu_sc_t18.tlef \
 		-cdl %l/latest/cdl/*.cdl ignore=topography compile-only \
 		-lef %l/latest/lef/*.lef compile-only \
 		-lib %l/latest/lib/*.lib \