fixed compiler error with GMP PR

.install/cmake/Modules/FindGMP.cmake

@@ -0,0 +1,24 @@
+# Try to find the GMP librairies
+#  GMP_FOUND - system has GMP lib
+#  GMP_INCLUDE_DIR - the GMP include directory
+#  GMP_LIBRARIES - Libraries needed to use GMP
+
+# Copyright (c) 2006, Laurent Montel, <montel@kde.org>
+#
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+
+if (GMP_INCLUDE_DIR AND GMP_LIBRARIES)
+  # Already in cache, be silent
+  set(GMP_FIND_QUIETLY TRUE)
+endif (GMP_INCLUDE_DIR AND GMP_LIBRARIES)
+
+find_path(GMP_INCLUDE_DIR NAMES gmp.h )
+find_library(GMP_LIBRARIES NAMES gmp libgmp )
+find_library(GMPXX_LIBRARIES NAMES gmpxx libgmpxx )
+MESSAGE(STATUS "GMP libs: " ${GMP_LIBRARIES} " " ${GMPXX_LIBRARIES} )
+
+include(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(GMP DEFAULT_MSG GMP_INCLUDE_DIR GMP_LIBRARIES)
+
+mark_as_advanced(GMP_INCLUDE_DIR GMP_LIBRARIES)

.travis.yml

@@ -10,6 +10,7 @@ addons:
     packages:
     - gcc-4.8
     - g++-4.8
+    - libgmp-dev
 #    - clang
 notifications:
   email:

CMakeLists.txt

@@ -14,7 +14,7 @@ list(FIND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES "${CMAKE_INSTALL_PREFIX}/lib"
 if("${isSystemDir}" STREQUAL "-1")
    set(CMAKE_INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib")
 endif("${isSystemDir}" STREQUAL "-1")
-set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_SOURCE_DIR}/cmake-modules)
+set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_SOURCE_DIR}/.install/cmake/Modules)
 
 #########
 # Flags #

include/chomp/Ring.h

@@ -141,7 +141,7 @@ class GMP_Integer {
   mpz_class x;
 public:
   GMP_Integer ( void ) : x ( 0 ) {}
-  GMP_Integer ( int64_t x ) : x(x) {}
+  GMP_Integer ( int32_t x ) : x(x) {} // GMP does not allow conversions from 64-bit types here, strangely
   GMP_Integer ( const mpz_class& x) : x(x) {}
 
   bool invertible ( void ) const {