diff --git a/cmake/external/gflags.cmake b/cmake/external/gflags.cmake
index dcbff05d0d418c2befcac4ebd884ec49a7f5cda3..dbd6c3b75e2d49f29649877a54c376a5a6b11572 100644
--- a/cmake/external/gflags.cmake
+++ b/cmake/external/gflags.cmake
@@ -39,8 +39,8 @@ ExternalProject_Add(
                     -DCMAKE_CXX_FLAGS_RELEASE=${CMAKE_CXX_FLAGS_RELEASE}
                     -DCMAKE_CXX_FLAGS_DEBUG=${CMAKE_CXX_FLAGS_DEBUG}
                     -DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}
-                    -DCMAKE_C_FLAGS_DEBUG=${DCMAKE_C_FLAGS_DEBUG}
-                    -DCMAKE_C_FLAGS_RELEASE=${DCMAKE_C_FLAGS_RELEASE}
+                    -DCMAKE_C_FLAGS_DEBUG=${CMAKE_C_FLAGS_DEBUG}
+                    -DCMAKE_C_FLAGS_RELEASE=${CMAKE_C_FLAGS_RELEASE}
                     -DBUILD_STATIC_LIBS=ON
                     -DCMAKE_INSTALL_PREFIX=${GFLAGS_INSTALL_DIR}
                     -DCMAKE_POSITION_INDEPENDENT_CODE=ON
diff --git a/cmake/external/glog.cmake b/cmake/external/glog.cmake
index 5184a83bdd9a3ddaabbb9d36d7bb95fda95d6a4d..a3f3c6adf304e91308ebe7e1d0cc976e9cc3bb60 100644
--- a/cmake/external/glog.cmake
+++ b/cmake/external/glog.cmake
@@ -50,8 +50,8 @@ ExternalProject_Add(
                     -DCMAKE_CXX_FLAGS_RELEASE=${CMAKE_CXX_FLAGS_RELEASE}
                     -DCMAKE_CXX_FLAGS_DEBUG=${CMAKE_CXX_FLAGS_DEBUG}
                     -DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}
-                    -DCMAKE_C_FLAGS_DEBUG=${DCMAKE_C_FLAGS_DEBUG}
-                    -DCMAKE_C_FLAGS_RELEASE=${DCMAKE_C_FLAGS_RELEASE}
+                    -DCMAKE_C_FLAGS_DEBUG=${CMAKE_C_FLAGS_DEBUG}
+                    -DCMAKE_C_FLAGS_RELEASE=${CMAKE_C_FLAGS_RELEASE}
                     -DCMAKE_INSTALL_PREFIX=${GLOG_INSTALL_DIR}
                     -DCMAKE_INSTALL_LIBDIR=${GLOG_INSTALL_DIR}/lib
                     -DCMAKE_POSITION_INDEPENDENT_CODE=ON
diff --git a/cmake/external/openblas.cmake b/cmake/external/openblas.cmake
index 8c172437d4aa4fe1e1de4c4e5f15746b3a221d1a..829641fb97c5866ff6d0f5d46c30f7922691a955 100644
--- a/cmake/external/openblas.cmake
+++ b/cmake/external/openblas.cmake
@@ -85,8 +85,8 @@ IF(NOT ${CBLAS_FOUND})
                 CMAKE_ARGS    -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
                 -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
                 -DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}
-                -DCMAKE_C_FLAGS_DEBUG=${DCMAKE_C_FLAGS_DEBUG}
-                -DCMAKE_C_FLAGS_RELEASE=${DCMAKE_C_FLAGS_RELEASE}
+                -DCMAKE_C_FLAGS_DEBUG=${CMAKE_C_FLAGS_DEBUG}
+                -DCMAKE_C_FLAGS_RELEASE=${CMAKE_C_FLAGS_RELEASE}
                 -DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}
                 -DCMAKE_CXX_FLAGS_RELEASE=${CMAKE_CXX_FLAGS_RELEASE}
                 -DCMAKE_CXX_FLAGS_DEBUG=${CMAKE_CXX_FLAGS_DEBUG}
diff --git a/cmake/external/protobuf.cmake b/cmake/external/protobuf.cmake
index 43b69e72ddba5f6fdc54f03279b0f017f4962c50..75ffabca7c2ae831662d8e7a275ecc475f6bd9cb 100644
--- a/cmake/external/protobuf.cmake
+++ b/cmake/external/protobuf.cmake
@@ -192,8 +192,8 @@ FUNCTION(build_protobuf TARGET_NAME BUILD_FOR_HOST)
             "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
             "-DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}"
             "-DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}"
-            "-DCMAKE_C_FLAGS_DEBUG=${DCMAKE_C_FLAGS_DEBUG}"
-            "-DCMAKE_C_FLAGS_RELEASE=${DCMAKE_C_FLAGS_RELEASE}"
+            "-DCMAKE_C_FLAGS_DEBUG=${CMAKE_C_FLAGS_DEBUG}"
+            "-DCMAKE_C_FLAGS_RELEASE=${CMAKE_C_FLAGS_RELEASE}"
             "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
             "-DCMAKE_CXX_FLAGS_RELEASE=${CMAKE_CXX_FLAGS_RELEASE}"
             "-DCMAKE_CXX_FLAGS_DEBUG=${CMAKE_CXX_FLAGS_DEBUG}"