docs: describe potential build issues

BUILD.md

@@ -0,0 +1,140 @@
+# Build Issues and Solutions
+
+## Prerequisites
+
+Check that you have **DashSync** repo next to the wallet repo.
+
+Make sure you're on the **master** branch for both DashSync and DashWallet.
+
+### Clang Version Check
+
+Check clang version:
+
+```bash
+clang++ --version
+```
+
+If you see homebrew version, this might cause issues with building. You need to switch to system version.
+
+```
+❌ InstalledDir: /opt/homebrew/opt/llvm/bin
+✅ InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
+```
+
+To unplug homebrew version, comment out the following in `~/.zshrc` or `~/.zsh_profile` (or `~/.bashrc` if you're using bash):
+
+```bash
+export PATH="/opt/homebrew/opt/llvm/bin:$PATH"
+```
+
+## Required Dependencies
+
+Install the following dependencies:
+
+- **cmake** (version 3.28.3 recommended)
+- **cbindgen**
+- **rust**
+
+> **Note:** cmake 4.0.0 or higher might cause issues with building. Version 3.28.3 is tested and works.
+> 
+> Download from: https://github.com/Kitware/CMake/releases/download/v3.28.3/cmake-3.28.3-macos-universal.dmg
+
+### Installation Commands
+
+```bash
+# Install CMake
+sudo "/Applications/CMake.app/Contents/bin/cmake-gui" --install
+
+# Install cbindgen
+brew install cbindgen
+
+# Install Rust
+curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
+```
+
+### Xcode Setup
+
+```bash
+xcode-select --install
+sudo xcodebuild -license accept
+```
+
+### Pod Installation
+
+Run from the wallet directory:
+
+```bash
+pod install --verbose
+```
+
+## Potential Issues and Solutions
+
+### Issue 1: CBind Generation Error
+
+**Error:**
+```
+Compiling rs-merk-verify-c-binding v0.1.3 (https://github.com/dashpay/rs-merk-verify-c-binding?branch=for-use-in-main-crate#930aeb2a)
+error: failed to run custom build command for `dash-spv-coinjoin v0.1.0 (/Users/username/Development/dash-shared-core/dash-spv-coinjoin)`
+```
+
+**Solution:** Install cbindgen if not already installed:
+
+```bash
+brew install cbindgen
+```
+
+---
+
+### Issue 2: Git Repository Error with DAPI-GRPC
+
+**Error:**
+```
+Installing DAPI-GRPC (0.22.0-dev.8)
+ > Git download
+     $ /usr/bin/git clone https://github.com/dashevo/dashsync-iOS.git
+     ...
+   fatal: not a git repository (or any of the parent directories): .git
+```
+
+**Solution:** Downgrade CocoaPods to version 1.15.2. This might require upgrading Ruby to version 3.3.0 or higher:
+
+```bash
+# Install Ruby
+brew install ruby
+
+# Install specific CocoaPods version
+sudo gem install cocoapods -v 1.15.2
+```
+
+**Alternative installation:**
+```bash
+sudo /opt/homebrew/opt/ruby/bin/gem install -n /usr/local/bin cocoapods -v 1.15.2
+```
+
+---
+
+### Issue 3: 'dash_shared_core.h' file not found
+
+**Problem:** dash-shared-core was not compiled properly due to various potential reasons.
+
+**Solution:** Check the build log for more details. Usually caused by missing dependencies (see above).
+
+## dash-shared-core Development
+
+If you want to make modifications to dash-shared-core, follow these steps:
+
+### Setup Steps
+
+1. **Place dash-shared-core in the correct location:**
+   Put dash-shared-core in the same directory as the wallet repo.
+
+2. **Remove DashSharedCore from DashSync.podspec:**
+   ```ruby
+   # s.dependency 'DashSharedCore', '0.5.1'
+   ```
+
+3. **Add local dash-shared-core to Podfile:**
+   In the wallet or DashSync example Podfile, add:
+   ```ruby
+   pod 'DashSharedCore', :path => '../dash-shared-core/'
+   ```

README.md

@@ -36,20 +36,18 @@ Open `DashWallet.xcworkspace` in Xcode and run the project.
 ## Requirements
 
 - Xcode 11
-- Dependency manager [CocoaPods](https://cocoapods.org). Install via `gem install cocoapods`
+- Dependency manager [CocoaPods](https://cocoapods.org). Install via `gem install cocoapods -v 1.15.2`
 
 ### DashPay Requirements
 
 Currently, DashPay wallet is under active development so it requires a few additional steps to make it work.
 
 1. Clone [DashSync](https://github.com/dashevo/dashsync-iOS) and [dapi-grpc](https://github.com/dashevo/dapi-grpc) repositories:  
 `git clone https://github.com/dashevo/dashsync-iOS.git DashSync`  
-`git clone https://github.com/dashevo/dapi-grpc.git dapi-grpc`
 
 To simplify developing process we use local podspec dependencies and it's important to preserve the following folder structure:
 ```
 ../DashSync/
-../dapi-grpc/
 ../dashwallet-ios/
 ```
 
@@ -64,6 +62,8 @@ To simplify developing process we use local podspec dependencies and it's import
 
 5. Run `pod install` in the wallet directory.
 
+See [BUILD.md](BUILD.md) for more details.
+
 ### Optional Requirements
 
 #### Objective-C Related