diff --git a/.gitignore b/.gitignore
index 0de981d68af0f435cb68b88d38eed2e1430990d1..49fc216a18952e650a7aa2a91a0744aa2ca2322e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -19,6 +19,7 @@ src/Trim*
 prep_plot
 
 # Generated Files
+confdefs
 *.ps
 *.sce
 *.ui.h
diff --git a/src/utilities/Makefile.am b/src/utilities/Makefile.am
index dcdb81e40f336afbdacff1b1cf170dc7367fbab9..2cb6ba599b4bb8580a3c31a601d4d1f943b41e62 100644
--- a/src/utilities/Makefile.am
+++ b/src/utilities/Makefile.am
@@ -4,6 +4,6 @@ SUBDIRS = aeromatic
 
 noinst_PROGRAMS = prep_plot
 
-prep_plot_CPPFLAGS = -I ../input_output
+prep_plot_CPPFLAGS = -I ${TOP_SRCDIR}/src/input_output
 prep_plot_SOURCES = prep_plot.cpp ../simgear/xml/easyxml.cxx plotXMLVisitor.cpp
 prep_plot_LDADD = -lexpat