Also consider reexported dylibs

[amesgen]

At some time in the past, reexported dylibs (marked as LC_REEXPORT_DYLIB) started to be ignored. This ofc leads to potentially missing dylibs on other machines.

It did work back in ce13cb585ead5237813b85e68fe530f085fc0a9e, and I think the bug was introduced as part of #50, so I am also mentioning @SCG82.

An example for a library which uses LC_REEXPORT_DYLIB: darwin.libiconv in nixpkgs.

Click to see otool -L of libiconv.dylib

``` otool -L $(nix-build -A darwin.libiconv '')/lib/libiconv.dylib ``` ``` /nix/store/qz8nr870hpdn6bdljjw8zzvd3sjjr941-libiconv-50/lib/libiconv.dylib: /nix/store/qz8nr870hpdn6bdljjw8zzvd3sjjr941-libiconv-50/lib/libiconv.dylib (compatibility version 7.0.0, current version 7.0.0) /nix/store/qz8nr870hpdn6bdljjw8zzvd3sjjr941-libiconv-50/lib/libiconv-nocharset.dylib (compatibility version 7.0.0, current version 7.0.0, reexport) /nix/store/qz8nr870hpdn6bdljjw8zzvd3sjjr941-libiconv-50/lib/libcharset.1.dylib (compatibility version 2.0.0, current version 2.0.0, reexport) /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1238.60.2) ```

Click to see otool -l of libiconv.dylib

``` otool -l $(nix-build -A darwin.libiconv '')/lib/libiconv.dylib ``` ``` /nix/store/qz8nr870hpdn6bdljjw8zzvd3sjjr941-libiconv-50/lib/libiconv.dylib: Load command 0 cmd LC_SEGMENT_64 cmdsize 232 segname __TEXT vmaddr 0x0000000000000000 vmsize 0x0000000000001000 fileoff 0 filesize 4096 maxprot 0x00000005 initprot 0x00000005 nsects 2 flags 0x0 Section sectname __text segname __TEXT addr 0x0000000000000fb0 size 0x0000000000000006 offset 4016 align 2^4 (16) reloff 0 nreloc 0 flags 0x80000400 reserved1 0 reserved2 0 Section sectname __unwind_info segname __TEXT addr 0x0000000000000fb8 size 0x0000000000000048 offset 4024 align 2^2 (4) reloff 0 nreloc 0 flags 0x00000000 reserved1 0 reserved2 0 Load command 1 cmd LC_SEGMENT_64 cmdsize 72 segname __LINKEDIT vmaddr 0x0000000000001000 vmsize 0x0000000000000068 fileoff 4096 filesize 104 maxprot 0x00000001 initprot 0x00000001 nsects 0 flags 0x0 Load command 2 cmd LC_ID_DYLIB cmdsize 104 name /nix/store/qz8nr870hpdn6bdljjw8zzvd3sjjr941-libiconv-50/lib/libiconv.dylib (offset 24) time stamp 1 Wed Dec 31 16:00:01 1969 current version 7.0.0 compatibility version 7.0.0 Load command 3 cmd LC_DYLD_INFO_ONLY cmdsize 48 rebase_off 0 rebase_size 0 bind_off 0 bind_size 0 weak_bind_off 0 weak_bind_size 0 lazy_bind_off 0 lazy_bind_size 0 export_off 4096 export_size 24 Load command 4 cmd LC_SYMTAB cmdsize 24 symoff 4128 nsyms 2 stroff 4160 strsize 40 Load command 5 cmd LC_DYSYMTAB cmdsize 80 ilocalsym 0 nlocalsym 0 iextdefsym 0 nextdefsym 1 iundefsym 1 nundefsym 1 tocoff 0 ntoc 0 modtaboff 0 nmodtab 0 extrefsymoff 0 nextrefsyms 0 indirectsymoff 0 nindirectsyms 0 extreloff 0 nextrel 0 locreloff 0 nlocrel 0 Load command 6 cmd LC_VERSION_MIN_MACOSX cmdsize 16 version 10.12 sdk 10.12 Load command 7 cmd LC_SOURCE_VERSION cmdsize 16 version 0.0 Load command 8 cmd LC_REEXPORT_DYLIB cmdsize 112 name /nix/store/qz8nr870hpdn6bdljjw8zzvd3sjjr941-libiconv-50/lib/libiconv-nocharset.dylib (offset 24) time stamp 2 Wed Dec 31 16:00:02 1969 current version 7.0.0 compatibility version 7.0.0 Load command 9 cmd LC_REEXPORT_DYLIB cmdsize 104 name /nix/store/qz8nr870hpdn6bdljjw8zzvd3sjjr941-libiconv-50/lib/libcharset.1.dylib (offset 24) time stamp 2 Wed Dec 31 16:00:02 1969 current version 2.0.0 compatibility version 2.0.0 Load command 10 cmd LC_LOAD_DYLIB cmdsize 56 name /usr/lib/libSystem.B.dylib (offset 24) time stamp 2 Wed Dec 31 16:00:02 1969 current version 1238.60.2 compatibility version 1.0.0 Load command 11 cmd LC_FUNCTION_STARTS cmdsize 16 dataoff 4120 datasize 8 Load command 12 cmd LC_DATA_IN_CODE cmdsize 16 dataoff 4128 datasize 0 ```

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Thanks for this great tool, it is extremely useful!

[SCG82]

Thanks!