Systick delay problem in KEIL STM32F407 descovery

Hello,I have tried to create a systick delay using systick interrupt as shown in the code bellow.

But It shows me those warnings shown bellow,and nothing happens on my STM32 shown bellow.
Where did i go wrong?
Thanks.

#include "stm32f407xx.h"

volatile uint16_t delay_count=0;
void SysTick_Handler(void)//called every 1ms
{
	if (delay_count>0)
	{
		 delay_count--;
	}
}
void delay_ms(uint16_t delay_temp)
{
	delay_count=delay_temp;
	while(delay_count){}
}
int main()
{ 
	 
	
	RCC->AHB1ENR|=(1uL<<3); //set thirdbit
	//GPIOD->MODER&=~(1uL<<31);//reset 0 on 31 01 to gpio_moder 31,30 bits in register 
	//GPIOD->MODER|=(1uL<<30);//set 1 on 30 output mode for pin 15 port D
	GPIOD->MODER=0x55000000;
	
	SysTick_Config(SystemCoreClock/1000);//1 ms interrupt
	
	GPIOD->OTYPER=0; //all register is push pull
	GPIOD->OSPEEDR=0;//speed low
	 //GPIOD->ODR|=(1<<15); //Sets pin 15 
 
	while(1)
		
	{
		 GPIOD->BSRR=(1uL<<15);
			 delay_ms(500);
     GPIOD->BSRR=(1uL<<(15+16));		
       delay_ms(500);

	}
}

Build target 'Target 1'
bob.c(3): warning: no previous extern declaration for non-static variable 'delay_count' [-Wmissing-variable-declarations]
volatile uint16_t delay_count=0;
^
bob.c(3): note: declare 'static' if the variable is not intended to be used outside of this translation unit
volatile uint16_t delay_count=0;
^
bob.c(4): warning: no previous prototype for function 'SysTick_Handler' [-Wmissing-prototypes]
void SysTick_Handler(void)//called every 1ms
^
bob.c(4): note: declare 'static' if the function is not intended to be used outside of this translation unit
void SysTick_Handler(void)//called every 1ms
^
static
bob.c(11): warning: no previous prototype for function 'delay_ms' [-Wmissing-prototypes]
void delay_ms(uint16_t delay_temp)
^
bob.c(11): note: declare 'static' if the function is not intended to be used outside of this translation unit
void delay_ms(uint16_t delay_temp)
^
static
3 warnings generated.
compiling bob.c...
linking...
Program Size: Code=600 RO-data=424 RW-data=4 ZI-data=1640
".\Objects\try1.axf" - 0 Error(s), 3 Warning(s).
Build Time Elapsed: 00:00:00
Load "C:\\Keil_v5\\less01\\Objects\\try1.axf"
Erase Done.
Programming Done.
Verify OK.
Application running ...
Flash Load finished at 13:12:31
Load "C:\\Keil_v5\\less01\\Objects\\try1.axf"
Erase Done.
Programming Done.
Verify OK.
Application running ...
Flash Load finished at 13:12:46