Statically compiled instructions fail for armv7 on raspberry pi 4

[Danrancan]

the instructions:
cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_FLAGS="-Ofast -m64 -march=native -mtune=native -flto -funroll-loops -ffunction-sections -fdata-sections -Wl,--gc-sections" -DCMAKE_CXX_FLAGS="-Ofast -m64 -march=native -mtune=native -flto -funroll-loops -ffunction-sections -fdata-sections -Wl,--gc-sections" -DCMAKE_INSTALL_PREFIX=./installed ..

don't work on a Raspberry Pi 4 armv7.

I believe the following command works with armv7, but is shows a warning:
cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_FLAGS="-Ofast -march=armv7-a -march=native -mtune=native -flto -funroll-loops -ffunction-sections -fdata-sections -Wl,--gc-sections" -DCMAKE_CXX_FLAGS="-Ofast -march=armv7-a -march=native -mtune=native -flto -funroll-loops -ffunction-sections -fdata-sections -Wl,--gc-sections" -DCMAKE_INSTALL_PREFIX=./installed ..

CMake Warning:
  Manually-specified variables were not used by the project:
    CMAKE_CXX_FLAGS

Please help fix this warning and help fix the instructions for compiling on a raspberry pi 3/4.

[abuits]

try:
cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=OFF -DCMAKE_INSTALL_PREFIX=./installed ..