I copied hyperbk's source tree:
cd hyperbk
mkdir -pv $LFS/usr/include/hyperbk/
cp . $LFS/usr/include/hyperbk/ -rv
When I was compiling musl, it outputs:
x86_64-lfs-hyperbolabsd-gcc -std=c99 -nostdinc -ffreestanding -fexcess-precision=standard -frounding-math -fno-strict-aliasing -Wa,--noexecstack -D_XOPEN_SOURCE=700 -I./arch/x86_64 -I./arch/generic -Iobj/src/internal -I./src/include -I./src/internal -Iobj/include -I./include -O2 -fno-align-jumps -fno-align-functions -fno-align-loops -fno-align-labels -fira-region=one -fira-hoist-pressure -freorder-blocks-algorithm=simple -fno-prefetch-loop-arrays -fno-tree-ch -pipe -fomit-frame-pointer -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -Wno-pointer-to-int-cast -Werror=implicit-function-declaration -Werror=implicit-int -Werror=pointer-sign -Werror=pointer-arith -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=discarded-qualifiers -Werror=discarded-array-qualifiers -Waddress -Warray-bounds -Wchar-subscripts -Wduplicate-decl-specifier -Winit-self -Wreturn-type -Wsequence-point -Wstrict-aliasing -Wunused-function -Wunused-label -Wunused-variable -I/mnt/lfs/usr/include -fPIC -fno-stack-protector -DCRT -c -o obj/crt/Scrt1.o crt/Scrt1.c
cp obj/crt/Scrt1.o lib/Scrt1.o
x86_64-lfs-hyperbolabsd-gcc -std=c99 -nostdinc -ffreestanding -fexcess-precision=standard -frounding-math -fno-strict-aliasing -Wa,--noexecstack -D_XOPEN_SOURCE=700 -I./arch/x86_64 -I./arch/generic -Iobj/src/internal -I./src/include -I./src/internal -Iobj/include -I./include -O2 -fno-align-jumps -fno-align-functions -fno-align-loops -fno-align-labels -fira-region=one -fira-hoist-pressure -freorder-blocks-algorithm=simple -fno-prefetch-loop-arrays -fno-tree-ch -pipe -fomit-frame-pointer -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -Wno-pointer-to-int-cast -Werror=implicit-function-declaration -Werror=implicit-int -Werror=pointer-sign -Werror=pointer-arith -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=discarded-qualifiers -Werror=discarded-array-qualifiers -Waddress -Warray-bounds -Wchar-subscripts -Wduplicate-decl-specifier -Winit-self -Wreturn-type -Wsequence-point -Wstrict-aliasing -Wunused-function -Wunused-label -Wunused-variable -I/mnt/lfs/usr/include -fno-stack-protector -DCRT -c -o obj/crt/crt1.o crt/crt1.c
cp obj/crt/crt1.o lib/crt1.o
x86_64-lfs-hyperbolabsd-gcc -std=c99 -nostdinc -ffreestanding -fexcess-precision=standard -frounding-math -fno-strict-aliasing -Wa,--noexecstack -D_XOPEN_SOURCE=700 -I./arch/x86_64 -I./arch/generic -Iobj/src/internal -I./src/include -I./src/internal -Iobj/include -I./include -O2 -fno-align-jumps -fno-align-functions -fno-align-loops -fno-align-labels -fira-region=one -fira-hoist-pressure -freorder-blocks-algorithm=simple -fno-prefetch-loop-arrays -fno-tree-ch -pipe -fomit-frame-pointer -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -Wno-pointer-to-int-cast -Werror=implicit-function-declaration -Werror=implicit-int -Werror=pointer-sign -Werror=pointer-arith -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=discarded-qualifiers -Werror=discarded-array-qualifiers -Waddress -Warray-bounds -Wchar-subscripts -Wduplicate-decl-specifier -Winit-self -Wreturn-type -Wsequence-point -Wstrict-aliasing -Wunused-function -Wunused-label -Wunused-variable -I/mnt/lfs/usr/include -fPIC -fno-stack-protector -DCRT -c -o obj/crt/rcrt1.o crt/rcrt1.c
cp obj/crt/rcrt1.o lib/rcrt1.o
cp obj/crt/x86_64/crti.o lib/crti.o
cp obj/crt/x86_64/crtn.o lib/crtn.o
x86_64-lfs-hyperbolabsd-gcc -std=c99 -nostdinc -ffreestanding -fexcess-precision=standard -frounding-math -fno-strict-aliasing -Wa,--noexecstack -D_XOPEN_SOURCE=700 -I./arch/x86_64 -I./arch/generic -Iobj/src/internal -I./src/include -I./src/internal -Iobj/include -I./include -O2 -fno-align-jumps -fno-align-functions -fno-align-loops -fno-align-labels -fira-region=one -fira-hoist-pressure -freorder-blocks-algorithm=simple -fno-prefetch-loop-arrays -fno-tree-ch -pipe -fomit-frame-pointer -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -Wno-pointer-to-int-cast -Werror=implicit-function-declaration -Werror=implicit-int -Werror=pointer-sign -Werror=pointer-arith -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=discarded-qualifiers -Werror=discarded-array-qualifiers -Waddress -Warray-bounds -Wchar-subscripts -Wduplicate-decl-specifier -Winit-self -Wreturn-type -Wsequence-point -Wstrict-aliasing -Wunused-function -Wunused-label -Wunused-variable -I/mnt/lfs/usr/include -c -o obj/src/aio/aio.o src/aio/aio.c
x86_64-lfs-hyperbolabsd-gcc -std=c99 -nostdinc -ffreestanding -fexcess-precision=standard -frounding-math -fno-strict-aliasing -Wa,--noexecstack -D_XOPEN_SOURCE=700 -I./arch/x86_64 -I./arch/generic -Iobj/src/internal -I./src/include -I./src/internal -Iobj/include -I./include -O2 -fno-align-jumps -fno-align-functions -fno-align-loops -fno-align-labels -fira-region=one -fira-hoist-pressure -freorder-blocks-algorithm=simple -fno-prefetch-loop-arrays -fno-tree-ch -pipe -fomit-frame-pointer -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -Wno-pointer-to-int-cast -Werror=implicit-function-declaration -Werror=implicit-int -Werror=pointer-sign -Werror=pointer-arith -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=discarded-qualifiers -Werror=discarded-array-qualifiers -Waddress -Warray-bounds -Wchar-subscripts -Wduplicate-decl-specifier -Winit-self -Wreturn-type -Wsequence-point -Wstrict-aliasing -Wunused-function -Wunused-label -Wunused-variable -I/mnt/lfs/usr/include -c -o obj/src/aio/aio_suspend.o src/aio/aio_suspend.c
x86_64-lfs-hyperbolabsd-gcc -std=c99 -nostdinc -ffreestanding -fexcess-precision=standard -frounding-math -fno-strict-aliasing -Wa,--noexecstack -D_XOPEN_SOURCE=700 -I./arch/x86_64 -I./arch/generic -Iobj/src/internal -I./src/include -I./src/internal -Iobj/include -I./include -O2 -fno-align-jumps -fno-align-functions -fno-align-loops -fno-align-labels -fira-region=one -fira-hoist-pressure -freorder-blocks-algorithm=simple -fno-prefetch-loop-arrays -fno-tree-ch -pipe -fomit-frame-pointer -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -Wno-pointer-to-int-cast -Werror=implicit-function-declaration -Werror=implicit-int -Werror=pointer-sign -Werror=pointer-arith -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=discarded-qualifiers -Werror=discarded-array-qualifiers -Waddress -Warray-bounds -Wchar-subscripts -Wduplicate-decl-specifier -Winit-self -Wreturn-type -Wsequence-point -Wstrict-aliasing -Wunused-function -Wunused-label -Wunused-variable -I/mnt/lfs/usr/include -c -o obj/src/aio/lio_listio.o src/aio/lio_listio.c
x86_64-lfs-hyperbolabsd-gcc -std=c99 -nostdinc -ffreestanding -fexcess-precision=standard -frounding-math -fno-strict-aliasing -Wa,--noexecstack -D_XOPEN_SOURCE=700 -I./arch/x86_64 -I./arch/generic -Iobj/src/internal -I./src/include -I./src/internal -Iobj/include -I./include -O2 -fno-align-jumps -fno-align-functions -fno-align-loops -fno-align-labels -fira-region=one -fira-hoist-pressure -freorder-blocks-algorithm=simple -fno-prefetch-loop-arrays -fno-tree-ch -pipe -fomit-frame-pointer -fno-unwind-tables -fno-asynchronous-unwind-tables -ffunction-sections -fdata-sections -Wno-pointer-to-int-cast -Werror=implicit-function-declaration -Werror=implicit-int -Werror=pointer-sign -Werror=pointer-arith -Werror=int-conversion -Werror=incompatible-pointer-types -Werror=discarded-qualifiers -Werror=discarded-array-qualifiers -Waddress -Warray-bounds -Wchar-subscripts -Wduplicate-decl-specifier -Winit-self -Wreturn-type -Wsequence-point -Wstrict-aliasing -Wunused-function -Wunused-label -Wunused-variable -I/mnt/lfs/usr/include -c -o obj/src/bsd/__tfork.o src/bsd/__tfork.c
In file included from ./src/include/../../include/unistd.h:59,
from ./src/include/unistd.h:4,
from src/bsd/__tfork.c:2:
/mnt/lfs/usr/include/hyperbk/nfs/nfs.h:102:2: error: unknown type name 'caddr_t'
caddr_t name; /* Client addr for connection based sockets */
^~~~~~~
/mnt/lfs/usr/include/hyperbk/nfs/nfs.h:109:2: error: unknown type name 'u_int32_t'
u_int32_t nsd_haddr; /* IP address of client */
^~~~~~~~~
/mnt/lfs/usr/include/hyperbk/nfs/nfs.h:110:16: error: field 'nsd_cr' has incomplete type
struct xucred nsd_cr; /* Cred. uid maps to */
^~~~~~
/mnt/lfs/usr/include/hyperbk/nfs/nfs.h:112:2: error: unknown type name 'u_char'
u_char *nsd_authstr; /* Auth string (ret) */
^~~~~~
/mnt/lfs/usr/include/hyperbk/nfs/nfs.h:114:2: error: unknown type name 'u_char'
u_char *nsd_verfstr;
^~~~~~
/mnt/lfs/usr/include/hyperbk/nfs/nfs.h:115:17: error: field 'nsd_timestamp' has incomplete type
struct timeval nsd_timestamp; /* timestamp from verifier */
^~~~~~~~~~~~~
/mnt/lfs/usr/include/hyperbk/nfs/nfs.h:116:2: error: unknown type name 'u_int32_t'
u_int32_t nsd_ttl; /* credential ttl (sec) */
^~~~~~~~~
/mnt/lfs/usr/include/hyperbk/nfs/nfs.h:139:18: error: 'NFS_NPROCS' undeclared here (not in a function); did you mean 'NFS_RETRANS'?
uint64_t rpccnt[NFS_NPROCS];
^~~~~~~~~~
NFS_RETRANS
In file included from ./src/include/unistd.h:4,
from src/bsd/__tfork.c:2:
./src/include/../../include/unistd.h:238:28: warning: 'struct __tfork' declared inside parameter list will not be visible outside of this definition or declaration
pid_t __tfork(const struct __tfork *, size_t);
^~~~~~~
./src/include/../../include/unistd.h:239:35: warning: 'struct __tfork' declared inside parameter list will not be visible outside of this definition or declaration
pid_t __tfork_thread(const struct __tfork *, size_t, void (*)(void *), void *);
^~~~~~~
./src/include/../../include/unistd.h:242:24: warning: 'struct __kbind' declared inside parameter list will not be visible outside of this definition or declaration
int kbind(const struct __kbind *, size_t, int64_t);
^~~~~~~
src/bsd/__tfork.c:5:28: warning: 'struct __tfork' declared inside parameter list will not be visible outside of this definition or declaration
pid_t __tfork(const struct __tfork *params, size_t psize)
^~~~~~~
src/bsd/__tfork.c:5:7: error: conflicting types for '__tfork'
pid_t __tfork(const struct __tfork *params, size_t psize)
^~~~~~~
In file included from ./src/include/unistd.h:4,
from src/bsd/__tfork.c:2:
./src/include/../../include/unistd.h:238:7: note: previous declaration of '__tfork' was here
pid_t __tfork(const struct __tfork *, size_t);
^~~~~~~
src/bsd/__tfork.c:11:15: warning: 'struct __tfork' declared inside parameter list will not be visible outside of this definition or declaration
const struct __tfork *params,
^~~~~~~
src/bsd/__tfork.c:10:7: error: conflicting types for '__tfork_thread'
pid_t __tfork_thread(
^~~~~~~~~~~~~~
In file included from ./src/include/unistd.h:4,
from src/bsd/__tfork.c:2:
./src/include/../../include/unistd.h:239:7: note: previous declaration of '__tfork_thread' was here
pid_t __tfork_thread(const struct __tfork *, size_t, void (*)(void *), void *);
^~~~~~~~~~~~~~
make: *** [Makefile:215: obj/src/bsd/__tfork.o] Error 1
I used these commands:
./configure CROSS_COMPILE=${LFS_TGT}- --prefix=/ --target=${CLFS_TGT}
echo "CFLAGS += -I$LFS/usr/include" >> config.mak
make -j1