diff --git a/SRC/INSTALL b/SRC/INSTALL
index 99c8123..67ee4e4 100644
--- a/SRC/INSTALL
+++ b/SRC/INSTALL
@@ -60,6 +60,15 @@ echoping in 32bits. With gcc:
 CFLAGS=-m32 ./configure --config-cache
 make
 
+If you get a:
+
+checking size of int... configure: error: cannot compute sizeof (int)
+
+it probably means configure's test programs cannot find libpopt (read
+config.log if you want a confirmation). Set LD_LIBRARY_PATH to include
+the directory where libpopt resides (it is not necessary to run
+echoping, just for the compilation).
+
 Standard "autoconf/configure" options are supported such as --prefix
 to set the installation root directory.