refactor : remove libcurl, use OpenSSL when available (#18828)

docs/backend/hexagon/CMakeUserPresets.json

@@ -23,7 +23,7 @@
             "GGML_OPENCL":      "ON",
             "GGML_HEXAGON":     "ON",
             "GGML_HEXAGON_FP32_QUANTIZE_GROUP_SIZE": "128",
-            "LLAMA_CURL":       "OFF"
+            "LLAMA_OPENSSL":    "OFF"
         }
     },
 
@@ -38,7 +38,7 @@
             "GGML_OPENCL":      "ON",
             "GGML_HEXAGON":     "ON",
             "GGML_HEXAGON_FP32_QUANTIZE_GROUP_SIZE": "128",
-            "LLAMA_CURL":       "OFF"
+            "LLAMA_OPENSSL":    "OFF"
         }
     },
 

docs/build-riscv64-spacemit.md

@@ -15,7 +15,7 @@ Below is the build script: it requires utilizing RISC-V vector instructions for
 cmake -B build \
     -DCMAKE_BUILD_TYPE=Release \
     -DGGML_CPU_RISCV64_SPACEMIT=ON \
-    -DLLAMA_CURL=OFF \
+    -DLLAMA_OPENSSL=OFF \
     -DGGML_RVV=ON \
     -DGGML_RV_ZFH=ON \
     -DGGML_RV_ZICBOP=ON \

docs/build.md

@@ -65,10 +65,10 @@ cmake --build build --config Release
       cmake --preset x64-windows-llvm-release
       cmake --build build-x64-windows-llvm-release
       ```
-- Curl usage is enabled by default and can be turned off with `-DLLAMA_CURL=OFF`. Otherwise you need to install development libraries for libcurl.
-  - **Debian / Ubuntu:** `sudo apt-get install libcurl4-openssl-dev`  # (or `libcurl4-gnutls-dev` if you prefer GnuTLS)
-  - **Fedora / RHEL / Rocky / Alma:** `sudo dnf install libcurl-devel`
-  - **Arch / Manjaro:** `sudo pacman -S curl`  # includes libcurl headers
+- If you want HTTPS/TLS features, you may install OpenSSL development libraries. If not installed, the project will build and run without SSL support.
+  - **Debian / Ubuntu:** `sudo apt-get install libssl-dev`
+  - **Fedora / RHEL / Rocky / Alma:** `sudo dnf install openssl-devel`
+  - **Arch / Manjaro:** `sudo pacman -S openssl`
 
 ## BLAS Build