fix linux compilation bugs
diff --git a/.waf-tools/default-compiler-flags.py b/.waf-tools/default-compiler-flags.py
index 9f15fcc..38468e8 100644
--- a/.waf-tools/default-compiler-flags.py
+++ b/.waf-tools/default-compiler-flags.py
@@ -108,6 +108,7 @@
                               '-Werror',
                               '-Wno-unused-parameter',
                               '-Wno-error=maybe-uninitialized', # Bug #1615
+                              '-fPIC',
                               ]
         return flags
 
@@ -119,6 +120,7 @@
                               '-Wall',
                               '-Wextra',
                               '-Wno-unused-parameter',
+                              '-fPIC',
                               ]
         return flags