Reverse dependencies of "isl"

Depended by: avr-gcc, gcc, gdb, sagemath

Library depended by:

• avr-gcc, gcc, gcc+w64
• (Circular dependencies) gcc+cross-loongarch64, gcc+cross-mips64r6el, gcc+cross-ppc64el, gcc+cross-amd64, gcc+cross-arm64, gcc+cross-loongson3, gcc+cross-riscv64