diff --git a/check/check-debug b/check/check-debug
index 01ac795..42f882e 100755
--- a/check/check-debug
+++ b/check/check-debug
@@ -14,7 +14,12 @@ Global variable definition 'pc_top_builddir' = '\$(top_builddir)'
 Error printing enabled by default due to use of output options besides --exists, --atleast/exact/max-version or --list-all. Value of --silence-errors: 0
 Error printing enabled
 $PACKAGE_VERSION"
-PKG_CONFIG_DEBUG_SPEW=1 run_test --version
+
+PKG_CONFIG_DEBUG_SPEW=1
+export PKG_CONFIG_DEBUG_SPEW
+run_test --version
+
+unset PKG_CONFIG_DEBUG_SPEW
 
 RESULT="Error printing enabled by default due to use of output options besides --exists, --atleast/exact/max-version or --list-all. Value of --silence-errors: 0
 Error printing enabled
diff --git a/check/check-path b/check/check-path
index 2a6be75..6b87637 100755
--- a/check/check-path
+++ b/check/check-path
@@ -5,7 +5,10 @@ set -e
 
 # PKG_CONFIG_PATH
 RESULT=""
-PKG_CONFIG_PATH="$srcdir/sub" run_test --exists sub1
+PKG_CONFIG_PATH="$srcdir/sub"
+export PKG_CONFIG_PATH
+run_test --exists sub1
+unset PKG_CONFIG_PATH
 
 # default pkg-config path, making sure to resolve the variables fully
 eval pc_path="$pc_path"
diff --git a/check/check-system-flags b/check/check-system-flags
index 632496c..6e0fdb1 100755
--- a/check/check-system-flags
+++ b/check/check-system-flags
@@ -23,10 +23,16 @@ run_test --libs system
 # Make sure that the full paths come out when the *_ALLOW_SYSTEM_*
 # variables are set
 RESULT="-I/usr/include"
-PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1 run_test --cflags system
+PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1
+export PKG_CONFIG_ALLOW_SYSTEM_CFLAGS
+run_test --cflags system
 
 RESULT="-L/usr/lib -lsystem"
-PKG_CONFIG_ALLOW_SYSTEM_LIBS=1 run_test --libs system
+PKG_CONFIG_ALLOW_SYSTEM_LIBS=1
+export PKG_CONFIG_ALLOW_SYSTEM_LIBS
+run_test --libs system
+
+unset PKG_CONFIG_ALLOW_SYSTEM_CFLAGS PKG_CONFIG_ALLOW_SYSTEM_LIBS
 
 # Set the system paths to something else and test that the output
 # contains the full paths
@@ -39,6 +45,9 @@ run_test --cflags system
 RESULT="-L/usr/lib -lsystem"
 run_test --libs system
 
+# Mark a bunch of stuff for export in the following loops
+export CPATH C_INCLUDE_PATH CPP_INCLUDE_PATH INCLUDE
+
 # Now check that the various GCC environment variables also update the
 # system include path
 for var in CPATH C_INCLUDE_PATH CPP_INCLUDE_PATH; do