This is the bash script I run to build C/C++ projects on Windows & macOS.

build.sh

#!/usr/bin/env

CMDLINE="$0 $@"

#-------------------------------------------------------------------------------

function usage {
    echo "Usage:"
    echo ""
    echo "  sh $0 [options] <sources> [-- ...]"
    echo ""
    echo "Options:"
    echo ""
    echo "  -std=<...>    Set C/C++ standard, e.g "
    echo "  -D<...>[=...] Define preprocessor macro, e.g.: -DNDEBUG=1"
    echo "  -O<...>       Set optimization level, e.g.: -O0, -O1, -O2, -O3, -Ofast, -Os"
    echo "  -g            Generate debug symbols."
    echo "  -o <dir>      Set output directory."
    echo "  -v            Enable verbose output."
    echo "  -x <ext>      Specify source language, e.g.: -x c, -x c++"
    echo "  --clean       Delete build artifacts."
    echo "  --clear       Clear the terminal before building."
    echo "  --            Run the compiled app, passing along remaining arguments."
    echo ""
}

#-------------------------------------------------------------------------------

function realpath {
    local path="${1//\\//}"
    if [ "$path" == "." ]; then
        echo "$(pwd)"
    elif [ "$path" == ".." ]; then
        echo "$(dirname "$(pwd)")"
    else
        echo "$(cd "$(dirname "$path")"; pwd)/$(basename "$path")"
    fi
}

#-------------------------------------------------------------------------------

CFLAGS="$CFLAGS -Wall -Werror -Wfatal-errors -Wno-comment -Wno-unused-variable"

SOURCES=()
while [ $# -gt 0 ]; do
    case $1 in
        -h|--help)
            usage
            exit 1
        ;;
        -g)
            CFLAGS="$CFLAGS $1"
            shift
        ;;
        -D*|-f*|-I*|-O*|-std=*|-W*)
            CFLAGS="$CFLAGS $1"
            shift
        ;;
        -x)
            CFLAGS="$CFLAGS $1 $2"
            shift
            shift
        ;;
        -o)
            APP_BUILD_ROOT="$2"
            shift
            shift
        ;;
        -t|--time)
            TIME=YES
            shift
        ;;
        -v|--verbose)
            VERBOSE=YES
            shift
        ;;
        --clean)
            CLEAN=YES
            shift
        ;;
        --clear)
            CLEAR=YES
            shift
        ;;
        --)
            RUN=YES
            shift
            break
        ;;
        -*)
            echo "unrecognized option: $1"
            echo ""
            usage
            exit 1
        ;;
        *)
            SOURCE="$(realpath $1)"
            SOURCES+=("$SOURCE")
            shift
        ;;
    esac
done

if [ ! $SOURCES ]; then
    usage
    exit 1
fi

#-------------------------------------------------------------------------------

if [ $CLEAR ]; then
    clear
fi

#-------------------------------------------------------------------------------

bold=$(tput bold)

normal=$(tput sgr0)

function hline {
    printf '%*s' "${COLUMNS:-$(tput cols)}" '' | tr ' ' _
}

#-------------------------------------------------------------------------------

function verbose {
    if [ $VERBOSE ]; then
        echo "$@" | \
        sed 's/ -/ \\\n    -/g' | \
        sed 's/ \// \\\n    \//g'
    fi
}

#-------------------------------------------------------------------------------

verbose "$CMDLINE"

#-------------------------------------------------------------------------------

APP_MAIN="${SOURCES[0]}"
APP_NAME="$(basename ${APP_MAIN%.*})"
APP_BUILD_ROOT="${APP_BUILD_ROOT:=$(dirname $APP_MAIN)/build}"

APP_SCRIPTS_DIR="$(realpath $(dirname $0))"
APP_TEMPLATES_DIR="$(dirname $APP_SCRIPTS_DIR)/templates"

case $(uname | tr '[:upper:]' '[:lower:]') in
    darwin*)
        APP_BUILD_OS=macos
        APP_BUILD_DIR="$APP_BUILD_ROOT/macos/$APP_NAME.app"
        APP_BIN="$APP_BUILD_DIR/Contents/MacOS/$APP_NAME"
    ;;
    linux*)
        APP_BUILD_OS=linux
        echo "unsupported operating system"
        exit 1
    ;;
    msys*|mingw*)
        APP_BUILD_OS=windows
        APP_BUILD_DIR="$APP_BUILD_ROOT/windows/$APP_NAME"
        APP_BIN="$APP_BUILD_DIR/$APP_NAME.exe"
        CFLAGS="${CFLAGS} -D_CRT_SECURE_NO_WARNINGS"
        CLANG_CFLAGS="${CLANG_CFLAGS} -fuse-ld=lld"
    ;;
    *)
        echo "unsupported operating system"
        exit 1
    ;;
esac

#-------------------------------------------------------------------------------

function execute {
    verbose "$@"
    if [ $TIME ]; then
        time --format="${bold}took %Es${normal}\n" "$@" || exit $?
    else
        "$@" || exit $?
    fi
    if [ $VERBOSE ]; then
        printf "${bold}\e[32m\xE2\x9C\x93 OK\e[39m${normal}\n"
    fi
}

#-------------------------------------------------------------------------------

# ensure $APP_BUILD_DIR exists
[ -d "$APP_BUILD_DIR" ] || execute mkdir -p "$APP_BUILD_DIR"

#-------------------------------------------------------------------------------

# copy template content into build dir
APP_TEMPLATE_DIR="$APP_TEMPLATES_DIR/$APP_BUILD_OS/."
[ -d "$APP_TEMPLATE_DIR" ] && execute cp -rf "$APP_TEMPLATE_DIR" "$APP_BUILD_DIR/"

#-------------------------------------------------------------------------------

# CC="${CC:=$(command -v cc || command -v gcc || command -v clang)}"
CC="${CC:=$(command -v clang)}"
# echo CC:"$CC"

case $CC in
    *clang*)
        CFLAGS="$CFLAGS $CLANG_CFLAGS"
    ;;
esac

case $($CC --version | tr '[:upper:]' '[:lower:]') in
    *msys*)
        CFLAGS="$CFLAGS -Wl,--subsystem,windows"
    ;;
esac

#-------------------------------------------------------------------------------

for SOURCE in "${SOURCES[@]}"; do
    CFLAGS="$CFLAGS $SOURCE"
done

execute "$CC" $CFLAGS -o"$APP_BIN"
# hline

#-------------------------------------------------------------------------------

if [ $RUN ]; then
    echo $''
    execute "$APP_BIN" "$@"
    # echo "$APP_BIN" returned "$?"
fi

#-------------------------------------------------------------------------------

if [ $CLEAN ]; then
    execute rm -rf  "$APP_BUILD_ROOT"
fi

#-------------------------------------------------------------------------------

exit

#-------------------------------------------------------------------------------

hello.cpp

///usr/bin/env sh scripts/build.sh \
    -Iinclude \
    -fno-rtti \
    -std=c++2a $0 "$@" \
    ;exit $?

#include <stdio.h>

int main() {
    puts("hello world");
    return 0;
}

terminal

> sh hello.cpp --

hello world