add /usr/lib to default search path for the dynamic linker

diff --git a/libc/Makeconfig b/libc/Makeconfig
index 1a9ad87..2d4d3f7 100644
--- a/libc/Makeconfig
+++ b/libc/Makeconfig
@@ -479,6 +479,9 @@ else
 default-rpath = $(libdir)
 endif
 
+# Add /usr/lib to default search path for the dynamic linker
+user-defined-trusted-dirs := /usr/lib
+
 ifndef link-extra-libs
 link-extra-libs = $(LDLIBS-$(@F))
 link-extra-libs-static = $(link-extra-libs)
