implicit pointer conversions are fatal on 64-bit systems

[LaMont Jones]

During rebuild testing of newlib_1.17.0-0ubuntu5:

Function `__libc_dlopen' implicitly converted to pointer at ../../../../../../../src/newlib/libc/sys/linux/net/nsswitch.c:349
Function `__libc_dlsym' implicitly converted to pointer at ../../../../../../../src/newlib/libc/sys/linux/net/nsswitch.c:375
Function `__libc_dlopen' implicitly converted to pointer at ../../../../../../../src/newlib/libc/sys/linux/iconv/gconv_dl.c:118
Function `__libc_dlsym' implicitly converted to pointer at ../../../../../../../src/newlib/libc/sys/linux/iconv/gconv_dl.c:121
Function `__libc_dlopen' implicitly converted to pointer at ../../../../../../../src/newlib/libc/sys/linux/iconv/gconv_trans.c:83
Function `__libc_dlsym' implicitly converted to pointer at ../../../../../../../src/newlib/libc/sys/linux/iconv/gconv_trans.c:89
Function `__setmntent' implicitly converted to pointer at ../../../../../../src/newlib/libc/sys/linux/fstab.c:139
Function `__setmntent' implicitly converted to pointer at ../../../../../../src/newlib/libc/sys/linux/internal_statvfs.c:60
Function `memalign' implicitly converted to pointer at ../../../../../../src/newlib/libc/sys/linux/malignr.c:6
Function `__getmntent_r' implicitly converted to pointer at ../../../../../../src/newlib/libc/sys/linux/mntent.c:66
Function `pvalloc' implicitly converted to pointer at ../../../../../../src/newlib/libc/sys/linux/pvallocr.c:6
Function `__setmntent' implicitly converted to pointer at ../../../../../../src/newlib/libc/sys/linux/internal_statvfs.c:60
Function `valloc' implicitly converted to pointer at ../../../../../../src/newlib/libc/sys/linux/vallocr.c:6

At some point during the life of an amd64 system, these bugs will prove fatal to the app.