another compiling problem (beginner)

Hi all, Sorry for bothering with another compiling problem. I had the following error while compiling osmocom-bb: configure:3246: arm-elf-gcc -Os -ffunction-sections -I/home/loretta/osmocom- bb/src/target/firmware/include -nostartfiles -nodefaultlibs conftest.c >&5 conftest.c: In function `main': conftest.c:15: warning: initialization makes pointer from integer without a cast /home/loretta/install/gnuarm-3.4.3/bin/../lib/gcc/arm-elf/3.4.3/../../../.. /arm-elf/bin/ld: warning: cannot find entry symbol _start; defaulting to 00008000 /tmp/ccgIuxoW.o(.text.main+0x14): In function `main': : undefined reference to `fopen' /tmp/ccgIuxoW.o(.text.main+0x1c): In function `main': : undefined reference to `ferror' /tmp/ccgIuxoW.o(.text.main+0x30): In function `main': : undefined reference to `fclose' collect2: ld returned 1 exit status configure:3250: $? = 1 configure:3287: result: configure: failed program was: | /* confdefs.h */ | #define PACKAGE_NAME "libosmocore" | #define PACKAGE_TARNAME "libosmocore" | #define PACKAGE_VERSION "UNKNOWN" | #define PACKAGE_STRING "libosmocore UNKNOWN" | #define PACKAGE_BUGREPORT &quot;openbsc-devel(a)lists.openbsc.org&quot; | #define PACKAGE_URL "" | #define PACKAGE "libosmocore" | #define VERSION "UNKNOWN" | /* end confdefs.h. */ | #include <stdio.h> | int | main () | { | FILE *f = fopen ("conftest.out", "w"); | return ferror (f) || fclose (f) != 0; | | ; | return 0; | } after hours of trying to understand how to fix this, I figured out that without the option -nodefaultlibs everything run smoothly. Now, the problem is that I do not understand much of what is going on and I wonder, do I need that option and hence should look for a different way of fixing the problem? Thanks for your help, Loretta