Loader issue

Compiled some source with the Arduino IDE and, at the end of compilation, the following loader errors appear:

/home/digysol/arduino-1.8.0/hardware/tools/arm/bin/../lib/gcc/arm-none-eabi/4.8.4/../../../../arm-none-eabi/lib/armv7e-m/libc.a(lib_a-openr.o): In function _open_r': openr.c:(.text._open_r+0x10): undefined reference to _open'
/home/digysol/arduino-1.8.0/hardware/tools/arm/bin/../lib/gcc/arm-none-eabi/4.8.4/../../../../arm-none-eabi/lib/armv7e-m/libc.a(lib_a-writer.o): In function _write_r': writer.c:(.text._write_r+0x10): undefined reference to _write'
collect2: error: ld returned 1 exit status

Welcome any suggestions as to what in the source could have triggered this error.

(deleted)

We have no idea what code you are compiling, for which Arduino, using what version of the IDE.

My crystal ball is usually more reliable than spycatcher2k's, but I dropped it, and had to send it in for repairs. It's due back on the 12th of never. If you need help before then, perhaps something will occur to you.