diff --git a/cmake/external/gflags.cmake b/cmake/external/gflags.cmake
index 5ed78bcf7545cc336aed60e4a024a895c7913c81..9f4c5d29b26a6f239e1613eda17d8708f33750cb 100644
--- a/cmake/external/gflags.cmake
+++ b/cmake/external/gflags.cmake
@@ -38,8 +38,8 @@ 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 2a34c96ab9639814542a1b376f3449aa49a7032d..8cd0455c16bf84909b735102e7fb1089744c4245 100644
--- a/cmake/external/glog.cmake
+++ b/cmake/external/glog.cmake
@@ -49,8 +49,8 @@ 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 844863a4258992ff2acf1acb9a37540b56cb9a1f..38e23d8ccfc4dba670a25347ee9d98c95ac4fb35 100644
--- a/cmake/external/openblas.cmake
+++ b/cmake/external/openblas.cmake
@@ -84,8 +84,8 @@ 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=${CMAKE_CXX_FLAGS_DEBUG}
diff --git a/cmake/external/protobuf.cmake b/cmake/external/protobuf.cmake
index bb1fcf356f987f610dd4808388992798d5f1fc73..e1c6df87c1f0827a8a6f3cb9f308561f9d627a4a 100644
--- a/cmake/external/protobuf.cmake
+++ b/cmake/external/protobuf.cmake
@@ -192,8 +192,8 @@ FUNCTION(build_protobuf TARGET_NAME BUILD_FOR_HOST)
             "-DCMAKE_CXX_COMPILER=${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}"