How to fix partitions if disk utility is not able to? I ask my question regardless of how I came to this point to make it more generally usable.

Disk utility is not able to fix my partitions. First partition is OS X (runs fine), second one is Windows (non bootable at the moment). I used rEFInd for booting.

It would be alright to delete Windows and just resize OS X. But how?



My partitions look like this

Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 234441614
Partitions will be aligned on 8-sector boundaries
Total free space is 56299597 sectors (26.8 GiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1              40          409639   200.0 MiB   EF00  EFI System Partition
   2          409640        98749479   46.9 GiB    AF00  BVMACPRO
   3        98749480       100019015   619.9 MiB   AB00  Recovery HD
   4       156317696       234440703   37.3 GiB    0700  BOOTCAMP


MBR looks like this:

Number  Boot  Start Sector   End Sector   Status      Code
   1                     1       409639   primary     0xEE
   2                409640     98749479   primary     0xAF
   3              98749480    100019015   primary     0xAB
   4             156317696    234440703   primary     0x0C


gpt output is:

$ sudo gpt -r show disk0
gpt show: disk0: Suspicious MBR at sector 0
      start       size  index  contents
          0          1         MBR
          1          1         Pri GPT header
          2         32         Pri GPT table
         34          6         
         40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
     409640   98339840      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
   98749480    1269536      3  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  100019016   56298680         
  156317696   78123008      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
  234440704        911         
  234441615         32         Sec GPT table
  234441647          1         Sec GPT header


fdisk

$ sudo fdisk /dev/disk0

Disk: /dev/disk0    geometry: 14593/255/63 [234441648 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] &lt;Unknown ID&gt;
 2: AF 1023 254  63 - 1023 254  63 [    409640 -   98339840] HFS+        
 3: AB 1023 254  63 - 1023 254  63 [  98749480 -    1269536] Darwin Boot 
 4: 0C 1023 254  63 - 1023 254  63 [ 156317696 -   78123008] Win95 FAT32L


I tried resizing the first partition via command line. 

$ sudo diskutil resizevolume /dev/disk0s2 R
Started partitioning on disk0s2 BVMACPRO
Verifying the disk
Checking file system
Performing live verification
Checking Journaled HFS Plus volume
Checking extents overflow file
Checking catalog hierarchy
Checking extended attributes file
Resizing
Error: -69742: The requested size change for the target disk or a related disk is too small; please try a different disk or partition, or make a larger change
You should be able to delete the Windows partition, which will allow you to resize the OS X partition. 

Normally you can simply click on the expansion icon located in the bottom corner of your OS X volume, which allows for easy resizing. However, Disk Utility won't allow this if there is another partition below the one you want to resize:

https://support.apple.com/kb/PH22240


  Enlarge a volume If you have multiple volumes on a device and one of
  them is running out of space, you may be able to enlarge it without
  losing any of the files on it.
  
  To enlarge a volume, you must delete the volume that comes after it on
  the device, then move the end point of the volume you want to enlarge
  into the freed space. You can’t enlarge the last volume on a device.