diff --git a/package/cc-tool/cc-tool.mk b/package/cc-tool/cc-tool.mk
index 7312bd384e..3a3f85ac42 100644
--- a/package/cc-tool/cc-tool.mk
+++ b/package/cc-tool/cc-tool.mk
@@ -14,4 +14,10 @@ CC_TOOL_DEPENDENCIES = boost libusb
 # Configure script "discovers" boost in /usr/local if not given explicitly
 CC_TOOL_CONF_OPTS = --with-boost=$(STAGING_DIR)/usr
 
+# Help boost.m4 find the Boost Regex library, which needs the pthread
+# library, but isn't detected using a modern (pkg-config) mechanism.
+ifeq ($(BR2_STATIC_LIBS),y)
+CC_TOOL_CONF_ENV += LIBS="-lpthread"
+endif
+
 $(eval $(autotools-package))