How to use a third party function library package with source codes in my QT Project?

[TOM&Jerry]

Hi, I am in trouble with how to use a third party function library package in my QT project.
This function library is based on MSVC in windows and GCC in Linux, also I have all the source codes edited by standard C language. I think i have three methods to use this function library in my QT project.

1. I can compile this function library in MSVC2005 and get the static library by using the solution included in the software package, also I can compile the function library with GCC ang get the static library by using the makefile included in the software package. So my question is Can I use these static libraries in my qt project? if can , how can i use ?

2. Because i have all source codes in C language. I want to transport this funcion library to QT environment. I have tried to do this using minGW32 compiler in Windows, but I found a fatal error in Windows is when the program call many times malloc() function to get memory, a NULL pointer can be returned that means the system has not empty memory, so the program exit. I don't the reason, but this error can't be happened in MSVC.

3. Also I tried to compile this source codes with MSVC compiler in QT environment, but I found a problem is all of souce files in my QT project is UTF-8 without BOM, the MSVC compiler can't compile these source file correctly because the MSVC compiler only can recognise the source file with UTF-8 BOM.

So want to get everyone's help.
Thanks!