Corrected the Makefile for sky130, which was unsetting PDKPATH to
prevent issues with existing environment variables, but also needs
to unset PDK_ROOT, or else an existing PDK_ROOT environment
variable will override the setting in magic while it is doing the
build, and screw up the build.

VERSION

diff --git a/VERSION b/VERSION
index 140bcfc..a2aba55 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.0.290
+1.0.291

sky130/Makefile.in

diff --git a/sky130/Makefile.in b/sky130/Makefile.in
index 071700e..9005dac 100644
--- a/sky130/Makefile.in
+++ b/sky130/Makefile.in
@@ -157,8 +157,10 @@
 TECH = sky130
 
 # The run-time environment uses PDKPATH to override the PDK location,
-# so prevent that from happening during PDK install.
+# so prevent that from happening during PDK install.  This will also
+# happen with PDK_ROOT, so avoid that as well.
 unexport PDKPATH 
+unexport PDK_ROOT 
 
 # If EF_STYLE is set to 1, then efabless naming conventions are
 # used, otherwise the generic naming conventions are used.