diff --git a/regression_test/Makefile.regression b/regression_test/Makefile.regression
index ad9bd18cfbe8de84733b9bb0787f6583b8e054fd..9357b044986dedba10c16effb973e69846e5e236 100644
--- a/regression_test/Makefile.regression
+++ b/regression_test/Makefile.regression
@@ -60,9 +60,9 @@ endif
 ifdef DYN
 DYNAMIC_SUFFIX = -dynamic
 ifeq ($(PLATFORM), WIN32)
-  export PATH:=$(TTCN3_DIR)/lib:$(PATH)
+  export PATH+=:$(TTCN3_DIR)/lib:
 else
-  export LD_LIBRARY_PATH:=$(TTCN3_DIR)/lib:$(LD_LIBRARY_PATH):$(ABS_SRC)
+  export LD_LIBRARY_PATH+=:$(TTCN3_DIR)/lib:
 endif 
 endif
 
diff --git a/regression_test/XML/XmlWorkflow/bin/prj2mk.pl b/regression_test/XML/XmlWorkflow/bin/prj2mk.pl
index 15e98cd716318f9d7b8782fca97ca06271a4d0ad..cce9403a234ebd3ad63e079696eebca5804cbf7a 100644
--- a/regression_test/XML/XmlWorkflow/bin/prj2mk.pl
+++ b/regression_test/XML/XmlWorkflow/bin/prj2mk.pl
@@ -133,8 +133,8 @@ while (<MAKEFILE_IN>) {
     print MAKEFILE_OUT <<MKF;
 TOPDIR := ../../..
 include   ../../../Makefile.regression
-export PATH:=\$(TTCN3_DIR)/bin:\$(PATH)
-export LD_LIBRARY_PATH:=\$(ABS_SRC):\$(TTCN3_DIR)/lib
+export PATH+=:\$(TTCN3_DIR)/bin:
+export LD_LIBRARY_PATH+=:\$(ABS_SRC):\$(TTCN3_DIR)/lib:
 MKF
   }
 }
diff --git a/regression_test/XML/XmlWorkflow/bin2/prj2mk.pl b/regression_test/XML/XmlWorkflow/bin2/prj2mk.pl
index 5dec96b7e5afcb19395cd947f823707f400192ae..6fff1c7f7b5541304ef0e88445d96d74f0ed8be7 100644
--- a/regression_test/XML/XmlWorkflow/bin2/prj2mk.pl
+++ b/regression_test/XML/XmlWorkflow/bin2/prj2mk.pl
@@ -130,8 +130,8 @@ while (<MAKEFILE_IN>) {
     print MAKEFILE_OUT <<MKF;
 TOPDIR := ../../..
 include   ../../../Makefile.regression
-export PATH:=\$(TTCN3_DIR)/bin:\$(PATH)
-export LD_LIBRARY_PATH:=\$(ABS_SRC):\$(TTCN3_DIR)/lib
+export PATH+=:\$(TTCN3_DIR)/bin:
+export LD_LIBRARY_PATH+=:\$(ABS_SRC):\$(TTCN3_DIR)/lib:
 MKF
   }
 }
diff --git a/regression_test/cfgFile/define/macro_reference/Makefile b/regression_test/cfgFile/define/macro_reference/Makefile
index 308046495a9ff8ceac3a1fb8f4db4664ba10827c..37842c4ac25436a0ea9d9cecdda26bf9c6c57431 100644
--- a/regression_test/cfgFile/define/macro_reference/Makefile
+++ b/regression_test/cfgFile/define/macro_reference/Makefile
@@ -34,9 +34,9 @@ endif
 
 ifdef DYN
 ifeq ($(PLATFORM), WIN32)
-  export PATH:=$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(PATH)
+  export PATH+=:$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 else
-  export LD_LIBRARY_PATH:=$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(LD_LIBRARY_PATH)
+  export LD_LIBRARY_PATH+=:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 endif 
 endif
 
diff --git a/regression_test/cfgFile/define/structured/Makefile b/regression_test/cfgFile/define/structured/Makefile
index 0846e458518e91b9b54e8241ff6209e0f30259d9..d131aedddfff5c9f2be8c2b931e8641c87c00b37 100644
--- a/regression_test/cfgFile/define/structured/Makefile
+++ b/regression_test/cfgFile/define/structured/Makefile
@@ -34,9 +34,9 @@ endif
 
 ifdef DYN
 ifeq ($(PLATFORM), WIN32)
-  export PATH:=$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(PATH)
+  export PATH+=:$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 else
-  export LD_LIBRARY_PATH:=$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(LD_LIBRARY_PATH)
+  export LD_LIBRARY_PATH+=:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 endif 
 endif
 
diff --git a/regression_test/cfgFile/module_parameters/assignment/Makefile b/regression_test/cfgFile/module_parameters/assignment/Makefile
index 81e5e5e60928277317d2df178b53e64b9a8a936c..97e3f6d6570880ad4060b2ec2c40a092ce6891b7 100644
--- a/regression_test/cfgFile/module_parameters/assignment/Makefile
+++ b/regression_test/cfgFile/module_parameters/assignment/Makefile
@@ -29,9 +29,9 @@ endif
 
 ifdef DYN
 ifeq ($(PLATFORM), WIN32)
-  export PATH:=$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(PATH)
+  export PATH+=:$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 else
-  export LD_LIBRARY_PATH:=$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(LD_LIBRARY_PATH)
+  export LD_LIBRARY_PATH+=:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 endif 
 endif
 
diff --git a/regression_test/cfgFile/module_parameters/concat/Makefile b/regression_test/cfgFile/module_parameters/concat/Makefile
index 3ec0e7c08d97af8d245814a648b1ab5edf0878bb..22e71edecb4f0d550a8490363cdcd1800c52ea41 100644
--- a/regression_test/cfgFile/module_parameters/concat/Makefile
+++ b/regression_test/cfgFile/module_parameters/concat/Makefile
@@ -29,9 +29,9 @@ endif
 
 ifdef DYN
 ifeq ($(PLATFORM), WIN32)
-  export PATH:=$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(PATH)
+  export PATH+=:$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 else
-  export LD_LIBRARY_PATH:=$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(LD_LIBRARY_PATH)
+  export LD_LIBRARY_PATH+=:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 endif 
 endif
 
diff --git a/regression_test/cfgFile/module_parameters/references/Makefile b/regression_test/cfgFile/module_parameters/references/Makefile
index 30f9e0d8a84770072b8faf5bd7f7f7dfbaa44019..bc0452d8a2c3cae2b9bf60b44d9133b39b397339 100644
--- a/regression_test/cfgFile/module_parameters/references/Makefile
+++ b/regression_test/cfgFile/module_parameters/references/Makefile
@@ -27,9 +27,9 @@ endif
 
 ifdef DYN
 ifeq ($(PLATFORM), WIN32)
-  export PATH:=$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(PATH)
+  export PATH+=:$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 else
-  export LD_LIBRARY_PATH:=$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(LD_LIBRARY_PATH)
+  export LD_LIBRARY_PATH+=:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 endif 
 endif
 
diff --git a/regression_test/cfgFile/ordered_include/Makefile b/regression_test/cfgFile/ordered_include/Makefile
index 0b313abac1d2f67ebf39c6c9bbdc7402c8e048dc..281268697220e135a2b91bcd7922b6b230e34628 100644
--- a/regression_test/cfgFile/ordered_include/Makefile
+++ b/regression_test/cfgFile/ordered_include/Makefile
@@ -30,9 +30,9 @@ endif
 
 ifdef DYN
 ifeq ($(PLATFORM), WIN32)
-  export PATH:=$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(PATH)
+  export PATH+=:$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 else
-  export LD_LIBRARY_PATH:=$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(LD_LIBRARY_PATH)
+  export LD_LIBRARY_PATH+=:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 endif 
 endif
 
diff --git a/regression_test/cfgFile/testport_parameters/Makefile b/regression_test/cfgFile/testport_parameters/Makefile
index d879490b9ca13a19b98bfc846141963914a8fe30..1012a28697102dd85950f633d585bfbfa14b1362 100644
--- a/regression_test/cfgFile/testport_parameters/Makefile
+++ b/regression_test/cfgFile/testport_parameters/Makefile
@@ -30,9 +30,9 @@ endif
 
 ifdef DYN
 ifeq ($(PLATFORM), WIN32)
-  export PATH:=$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(PATH)
+  export PATH+=:$(TTCN3_DIR)/lib:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 else
-  export LD_LIBRARY_PATH:=$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):$(LD_LIBRARY_PATH)
+  export LD_LIBRARY_PATH+=:$(ABS_SRC)/$(DIR_SINGLE):$(ABS_SRC)/$(DIR_PARALLEL):
 endif 
 endif