diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,7 +17,7 @@
 ADD_DEFINITIONS(-DHAVE_CONFIG_H)
 
 INCLUDE(CheckTypeSize)
-CHECK_TYPE_SIZE("long long" LONG_LONG)
+CHECK_TYPE_SIZE("long long" LEMON_LONG_LONG)
 
 ENABLE_TESTING()
 
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -27,7 +27,7 @@
 dnl Check the existence of long long type.
 AC_CHECK_TYPE(long long, [long_long_found=yes], [long_long_found=no])
 if test x"$long_long_found" = x"yes"; then
-  AC_DEFINE([HAVE_LONG_LONG], [1], [Define to 1 if you have long long.])
+  AC_DEFINE([LEMON_HAVE_LONG_LONG], [1], [Define to 1 if you have long long.])
 fi
 
 dnl Checks for programs.
diff --git a/lemon/bits/default_map.h b/lemon/bits/default_map.h
--- a/lemon/bits/default_map.h
+++ b/lemon/bits/default_map.h
@@ -97,7 +97,7 @@
   };
 
 
-#if defined HAVE_LONG_LONG
+#if defined LEMON_HAVE_LONG_LONG
 
   // long long
   template <typename _Graph, typename _Item>
diff --git a/lemon/config.h.cmake b/lemon/config.h.cmake
--- a/lemon/config.h.cmake
+++ b/lemon/config.h.cmake
@@ -1,1 +1,1 @@
-#cmakedefine HAVE_LONG_LONG 1
\ No newline at end of file
+#cmakedefine LEMON_HAVE_LONG_LONG 1
diff --git a/lemon/config.h.in b/lemon/config.h.in
--- a/lemon/config.h.in
+++ b/lemon/config.h.in
@@ -1,8 +1,8 @@
 /* Define to 1 if you have CPLEX. */
-#undef HAVE_CPLEX
+#undef LEMON_HAVE_CPLEX
 
 /* Define to 1 if you have GLPK. */
-#undef HAVE_GLPK
+#undef LEMON_HAVE_GLPK
 
 /* Define to 1 if you have long long */
-#undef HAVE_LONG_LONG
+#undef LEMON_HAVE_LONG_LONG
diff --git a/m4/lx_check_cplex.m4 b/m4/lx_check_cplex.m4
--- a/m4/lx_check_cplex.m4
+++ b/m4/lx_check_cplex.m4
@@ -61,7 +61,7 @@
     LIBS="$lx_save_libs"
 
     if test x"$lx_cplex_found" = x"yes"; then
-      AC_DEFINE([HAVE_CPLEX], [1], [Define to 1 if you have CPLEX.])
+      AC_DEFINE([LEMON_HAVE_CPLEX], [1], [Define to 1 if you have CPLEX.])
       AC_MSG_RESULT([yes])
     else
       CPLEX_CFLAGS=""
diff --git a/m4/lx_check_glpk.m4 b/m4/lx_check_glpk.m4
--- a/m4/lx_check_glpk.m4
+++ b/m4/lx_check_glpk.m4
@@ -59,7 +59,7 @@
     LIBS="$lx_save_libs"
 
     if test x"$lx_glpk_found" = x"yes"; then
-      AC_DEFINE([HAVE_GLPK], [1], [Define to 1 if you have GLPK.])
+      AC_DEFINE([LEMON_HAVE_GLPK], [1], [Define to 1 if you have GLPK.])
       AC_MSG_RESULT([yes])
     else
       GLPK_CFLAGS=""
diff --git a/m4/lx_check_soplex.m4 b/m4/lx_check_soplex.m4
--- a/m4/lx_check_soplex.m4
+++ b/m4/lx_check_soplex.m4
@@ -55,7 +55,7 @@
     LIBS="$lx_save_libs"
 
     if test x"$lx_soplex_found" = x"yes"; then
-      AC_DEFINE([HAVE_SOPLEX], [1], [Define to 1 if you have SOPLEX.])
+      AC_DEFINE([LEMON_HAVE_SOPLEX], [1], [Define to 1 if you have SOPLEX.])
       AC_MSG_RESULT([yes])
     else
       SOPLEX_CXXFLAGS=""