Fix error when finding the jsoncpp library (#356)

.travis.yml

@@ -3,7 +3,7 @@ matrix:
     - os: linux
       dist: xenial
     - os: osx
-      osx_image: xcode11
+      osx_image: xcode11.3
 
 sudo: required
 
@@ -38,6 +38,7 @@ addons:
     - lz4
     - mariadb
     - sqlite3
+    update: true
 before_install:
   - wget https://github.com/google/googletest/archive/release-1.10.0.tar.gz
   - tar xf release-1.10.0.tar.gz

cmake_modules/FindJsoncpp.cmake

@@ -13,8 +13,9 @@
 # only look in default directories
 find_path(
 	JSONCPP_INCLUDE_DIR 
-	NAMES jsoncpp/json/json.h json/json.h
+	NAMES json/json.h
 	DOC "jsoncpp include dir"
+	PATH_SUFFIXES jsoncpp
 )
 
 find_library(
@@ -43,20 +44,6 @@ if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
 
 endif()
 
-# find JSONCPP_INCLUDE_PREFIX
-find_path(
-	JSONCPP_INCLUDE_PREFIX
-	NAMES json.h
-	PATH_SUFFIXES jsoncpp/json json
-)
-
-if (${JSONCPP_INCLUDE_PREFIX} MATCHES "jsoncpp")
-	set(JSONCPP_INCLUDE_PREFIX "jsoncpp")
-	set(JSONCPP_INCLUDE_DIRS "${JSONCPP_INCLUDE_DIRS}/jsoncpp")
-else()
-	set(JSONCPP_INCLUDE_PREFIX "")
-endif()
-
 
 # handle the QUIETLY and REQUIRED arguments and set JSONCPP_FOUND to TRUE
 # if all listed variables are TRUE, hide their existence from configuration view