diff -purN gdal-2.3.1.orig/configure.ac gdal-2.3.1/configure.ac
--- gdal-2.3.1.orig/configure.ac	2018-07-17 14:10:15.236559853 +0200
+++ gdal-2.3.1/configure.ac	2018-07-17 14:21:49.213424507 +0200
@@ -2879,7 +2879,7 @@ else
             echo "#include <string>" > testnewabi.cpp
             echo "namespace NCS { class CString { public: static std::wstring Utf8Decode (const std::string &sUtf8); }; }" >> testnewabi.cpp
             echo "int main() { return static_cast<int>(NCS::CString::Utf8Decode(std::string()).size()); }" >> testnewabi.cpp
-            if test -z "`$${CXX} ${CXXFLAGS} ${CPPFLAGS} testnewabi.cpp -L$with_ecw/$ecw_license_type/lib/newabi/$ECW_ARCH/$ECW_CONF -lNCSEcw -o testnewabi 2>&1`" ; then
+            if test -z "`${CXX} ${CXXFLAGS} ${CPPFLAGS} testnewabi.cpp -L$with_ecw/$ecw_license_type/lib/newabi/$ECW_ARCH/$ECW_CONF -lNCSEcw -o testnewabi 2>&1`" ; then
                 ECW_LIBDIR=$with_ecw/$ecw_license_type/lib/newabi/$ECW_ARCH/$ECW_CONF
                 ECW_LIBS="-L$ECW_LIBDIR -lNCSEcw $ECW_FRAMEWORK_COCOA"
                 with_ecw=$with_ecw/$ecw_license_type