update readme

Author: anutosh491

Emscripten-build-instructions.md

@@ -125,9 +125,10 @@ mkdir build
 cd build
 emcmake cmake \
           -DCMAKE_BUILD_TYPE=Release                                     \
+          -DCMAKE_PREFIX_PATH=$PREFIX                                    \
           -DCMAKE_INSTALL_PREFIX=$PREFIX                                 \
           -DXEUS_CPP_EMSCRIPTEN_WASM_BUILD=ON                            \
-          -DCMAKE_FIND_ROOT_PATH_MODE_PACKAGE=$PREFIX                    \
+          -DCMAKE_FIND_ROOT_PATH_MODE_PACKAGE=ON                         \
           -DCppInterOp_DIR="$CPPINTEROP_BUILD_DIR/lib/cmake/CppInterOp"  \
           -DSYSROOT_PATH=$SYSROOT_PATH                                   \
           ..

docs/Emscripten-build-instructions.rst

@@ -145,9 +145,10 @@ build folder, you can build the wasm version of xeus-cpp by executing
    cd build
    emcmake cmake \
            -DCMAKE_BUILD_TYPE=Release                                     \
+           -DCMAKE_PREFIX_PATH=$PREFIX                                    \
            -DCMAKE_INSTALL_PREFIX=$PREFIX                                 \
            -DXEUS_CPP_EMSCRIPTEN_WASM_BUILD=ON                            \
-           -DCMAKE_FIND_ROOT_PATH_MODE_PACKAGE=$PREFIX                    \
+           -DCMAKE_FIND_ROOT_PATH_MODE_PACKAGE=ON                         \
            -DCppInterOp_DIR="$CPPINTEROP_BUILD_DIR/lib/cmake/CppInterOp"  \
            -DSYSROOT_PATH=$SYSROOT_PATH                                   \
            ..