diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index b723f02..1d92c80 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -450,35 +450,55 @@
 
 # Make sure the tools we need are available.
 pre_check_tools () {
-    ARMC5_CC="$ARMC5_BIN_DIR/armcc"
-    ARMC5_AR="$ARMC5_BIN_DIR/armar"
-    ARMC6_CC="$ARMC6_BIN_DIR/armclang"
-    ARMC6_AR="$ARMC6_BIN_DIR/armar"
+    # Build the list of variables to pass to output_env.sh.
+    set env
 
-    # To avoid setting OpenSSL and GnuTLS for each call to compat.sh and ssl-opt.sh
-    # we just export the variables they require
-    export OPENSSL_CMD="$OPENSSL"
-    export GNUTLS_CLI="$GNUTLS_CLI"
-    export GNUTLS_SERV="$GNUTLS_SERV"
+    case " $RUN_COMPONENTS " in
+        # Require OpenSSL and GnuTLS if running any tests (as opposed to
+        # only doing builds). Not all tests run OpenSSL and GnuTLS, but this
+        # is a good enough approximation in practice.
+        *" test_"*)
+            # To avoid setting OpenSSL and GnuTLS for each call to compat.sh
+            # and ssl-opt.sh, we just export the variables they require.
+            export OPENSSL_CMD="$OPENSSL"
+            export GNUTLS_CLI="$GNUTLS_CLI"
+            export GNUTLS_SERV="$GNUTLS_SERV"
+            # Avoid passing --seed flag in every call to ssl-opt.sh
+            if [ -n "${SEED-}" ]; then
+                export SEED
+            fi
+            set "$@" OPENSSL="$OPENSSL" OPENSSL_LEGACY="$OPENSSL_LEGACY"
+            set "$@" GNUTLS_CLI="$GNUTLS_CLI" GNUTLS_SERV="$GNUTLS_SERV"
+            set "$@" GNUTLS_LEGACY_CLI="$GNUTLS_LEGACY_CLI"
+            set "$@" GNUTLS_LEGACY_SERV="$GNUTLS_LEGACY_SERV"
+            check_tools "$OPENSSL" "$OPENSSL_LEGACY" \
+                        "$GNUTLS_CLI" "$GNUTLS_SERV" \
+                        "$GNUTLS_LEGACY_CLI" "$GNUTLS_LEGACY_SERV"
+            ;;
+    esac
 
-    # Avoid passing --seed flag in every call to ssl-opt.sh
-    if [ -n "${SEED-}" ]; then
-        export SEED
-    fi
+    case " $RUN_COMPONENTS " in
+        *_doxygen[_\ ]*) check_tools "doxygen" "dot";;
+    esac
 
-    check_tools "$OPENSSL" "$OPENSSL_LEGACY" "$GNUTLS_CLI" "$GNUTLS_SERV" \
-                "$GNUTLS_LEGACY_CLI" "$GNUTLS_LEGACY_SERV" "doxygen" "dot" \
-                "arm-none-eabi-gcc" "i686-w64-mingw32-gcc"
-    case $RUN_COMPONENTS in
+    case " $RUN_COMPONENTS " in
+        *_arm_none_eabi_gcc[_\ ]*) check_tools "arm-none-eabi-gcc";;
+    esac
+
+    case " $RUN_COMPONENTS " in
+        *_mingw[_\ ]*) check_tools "i686-w64-mingw32-gcc";;
+    esac
+
+    case " $RUN_COMPONENTS " in
         *_armcc*|*_yotta*)
+            ARMC5_CC="$ARMC5_BIN_DIR/armcc"
+            ARMC5_AR="$ARMC5_BIN_DIR/armar"
+            ARMC6_CC="$ARMC6_BIN_DIR/armclang"
+            ARMC6_AR="$ARMC6_BIN_DIR/armar"
             check_tools "$ARMC5_CC" "$ARMC5_AR" "$ARMC6_CC" "$ARMC6_AR";;
     esac
 
     msg "info: output_env.sh"
-    set env
-    set "$@" OPENSSL="$OPENSSL" OPENSSL_LEGACY="$OPENSSL_LEGACY"
-    set "$@" GNUTLS_CLI="$GNUTLS_CLI" GNUTLS_SERV="$GNUTLS_SERV"
-    set "$@" GNUTLS_LEGACY_CLI="$GNUTLS_LEGACY_CLI" GNUTLS_LEGACY_SERV="$GNUTLS_LEGACY_SERV"
     case $RUN_COMPONENTS in
         *_armcc*|*_yotta*)
             set "$@" ARMC5_CC="$ARMC5_CC" ARMC6_CC="$ARMC6_CC" RUN_ARMCC=1;;