Allow PDK_PATH to be user-specified
diff --git a/verilog/dv/caravel/mgmt_soc/gpio/Makefile b/verilog/dv/caravel/mgmt_soc/gpio/Makefile
index fcbea22..5a0c95d 100644
--- a/verilog/dv/caravel/mgmt_soc/gpio/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/gpio/Makefile
@@ -4,7 +4,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/hkspi/Makefile b/verilog/dv/caravel/mgmt_soc/hkspi/Makefile
index d8652ee..91e36f1 100644
--- a/verilog/dv/caravel/mgmt_soc/hkspi/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/hkspi/Makefile
@@ -5,7 +5,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/mem/Makefile b/verilog/dv/caravel/mgmt_soc/mem/Makefile
index 3d72290..1b791ce 100644
--- a/verilog/dv/caravel/mgmt_soc/mem/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/mem/Makefile
@@ -5,7 +5,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/mprj_ctrl/Makefile b/verilog/dv/caravel/mgmt_soc/mprj_ctrl/Makefile
index aba8479..8565a6b 100644
--- a/verilog/dv/caravel/mgmt_soc/mprj_ctrl/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/mprj_ctrl/Makefile
@@ -5,7 +5,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/pass_thru/Makefile b/verilog/dv/caravel/mgmt_soc/pass_thru/Makefile
index 2e0eae5..2d91c92 100644
--- a/verilog/dv/caravel/mgmt_soc/pass_thru/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/pass_thru/Makefile
@@ -5,7 +5,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/perf/Makefile b/verilog/dv/caravel/mgmt_soc/perf/Makefile
index 1c36a58..e885eb4 100644
--- a/verilog/dv/caravel/mgmt_soc/perf/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/perf/Makefile
@@ -4,7 +4,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/pll/Makefile b/verilog/dv/caravel/mgmt_soc/pll/Makefile
index 2698fc1..31bac9e 100644
--- a/verilog/dv/caravel/mgmt_soc/pll/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/pll/Makefile
@@ -4,7 +4,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/sysctrl/Makefile b/verilog/dv/caravel/mgmt_soc/sysctrl/Makefile
index 9dd652f..d07464b 100644
--- a/verilog/dv/caravel/mgmt_soc/sysctrl/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/sysctrl/Makefile
@@ -4,7 +4,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/timer/Makefile b/verilog/dv/caravel/mgmt_soc/timer/Makefile
index ea70d00..0f0bdb9 100644
--- a/verilog/dv/caravel/mgmt_soc/timer/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/timer/Makefile
@@ -4,7 +4,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/timer2/Makefile b/verilog/dv/caravel/mgmt_soc/timer2/Makefile
index 5081080..9fdcf04 100644
--- a/verilog/dv/caravel/mgmt_soc/timer2/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/timer2/Makefile
@@ -4,7 +4,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/mgmt_soc/uart/Makefile b/verilog/dv/caravel/mgmt_soc/uart/Makefile
index ea6a44f..e6fd284 100644
--- a/verilog/dv/caravel/mgmt_soc/uart/Makefile
+++ b/verilog/dv/caravel/mgmt_soc/uart/Makefile
@@ -5,7 +5,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/user_proj_example/io_ports/Makefile b/verilog/dv/caravel/user_proj_example/io_ports/Makefile
index e07c74a..2d5a749 100644
--- a/verilog/dv/caravel/user_proj_example/io_ports/Makefile
+++ b/verilog/dv/caravel/user_proj_example/io_ports/Makefile
@@ -4,7 +4,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/user_proj_example/la_test1/Makefile b/verilog/dv/caravel/user_proj_example/la_test1/Makefile
index 9a2dfc7..b026dbc 100644
--- a/verilog/dv/caravel/user_proj_example/la_test1/Makefile
+++ b/verilog/dv/caravel/user_proj_example/la_test1/Makefile
@@ -4,7 +4,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES:
 
diff --git a/verilog/dv/caravel/user_proj_example/la_test2/Makefile b/verilog/dv/caravel/user_proj_example/la_test2/Makefile
index 2519aa0..397a862 100644
--- a/verilog/dv/caravel/user_proj_example/la_test2/Makefile
+++ b/verilog/dv/caravel/user_proj_example/la_test2/Makefile
@@ -4,7 +4,7 @@
 BEHAVIOURAL_MODELS = ../../ 
 
 GCC_PATH=/ef/apps/bin
-PDK_PATH=/ef/tech/SW/sky130A
+PDK_PATH?=/ef/tech/SW/sky130A
 
 .SUFFIXES: